How To Tell If Your Door Has Been Opened: 5 Telltale Signs

You’ve come home from work, opened the front door, dropped your keys on the hall table and turned on the lights. But……. something doesn’t feel right. You stop dead. Your ears are on high alert – what is that sound? You cautiously make your way further into the house, looking intently all round. Nothing seems to be amiss but the hairs on the back of your neck are standing up and the adrenalin is spiking. “Hello?” you nervously call out, “anyone here?” You grab the nearest thing that could be used as a weapon – that awful vase Aunty Susan gave your wife last Christmas – and continue your stealthy creeping. And then! You jump ten feet high as Sprinkles the Siamese cat scampers around a corner tossing a little mouse in the air in that cruel way that cats have. Sinking into the nearest chair, you tenderly place Aunty Susan’s vase down and attempt to lower your heart rate and catch your breath.

This incident – which will soon make you smile and possibly even laugh, but not quite yet – gets you thinking.  What if someone actually was inside your house?  What if someone had opened the front door and got inside?  How would you know?

In this article, we are going to explore some of the signs that you can look for to assess whether your door has been opened by an intruder.

Table of Contents

Signs of Lock Picking
Signs of Breaking Through the Door / Frame
Signs of Using the Door Handle / Knob
Signs on the Outside
Signs on the Inside
Tips to Stay Safe
Some Questions People Ask

5 Tell Tale Signs That Someone Has Tried (or succeeded!) in Opening Your Door

1. Signs of Lock Picking

Picking a LockAn intruder has a number of methods he can use to try and break into your house.  One of these is lock picking. Check to see if your lock has been tampered with. You need to look for dents or scuff marks around the keyhole. A burglar in a hurry is very likely to use force when trying to enter a door. This is the messiest method and will cause some very obvious damage. The lock will likely be bashed in, or they might try to drill through the deadbolt.  No prizes for knowing that someone has tried, or succeeded, in breaking into your home for this one. However, even if force is used, it can be done in such a way that the damage is less obvious.

Look closely at your door and see if there are any paint circles – this indicates that the lock fixture has been moved. A potential intruder has loosened the lock and then placed it back in a slightly different position. Check to see if the deadbolt or the latch looks bent or damaged. You might also want to check to see if the door or doorframe appears warped. Another sign that someone has tried to pick your lock is if, when you insert your key into the door, it is more difficult to turn than before.  This could mean that there is pin deformation as a result of bumping or picking of the lock.

  • What is Bumping?

There is a secret technique that all locksmiths, and many burglars, know called “bumping”. This method opens locks quickly. A burglar will file down the teeth of a key to form sharp points. This is called a “bump key”. The bump key is then inserted into the lock and then withdrawn by one click. It is then stuck sharply with something like a stone or hammer and withdrawn one click again.  This process is repeated until all the tumblers have been caught. The burglar can then turn the key and the door opens.

This method can leave very little trace marks if done well. The amateur burglar, however, might be a bit too hasty and leave some telltale marks.  These could be:

  1. Nicks at the edge of the keyhole
  2. Little shiny bits of metal scattered about
  • Picking

This is the most traditional way that locks are tampered with. A burglar will use tools like small flat screwdrivers. One will be inserted into the lock in order to turn the lock and the “pick” will then be used to rake the tumblers. This method takes a bit more skill than bumping. It is a gentler method and is therefore unlikely to leave much trace evidence. However, as the tools wiggle around in the lock they do cut into the metal and leave a few marks. Keep an eye out for very small scratch marks around the keyhole.

If you find any evidence that your lock has been picked, call a locksmith to replace the lock right away.

  • Credit Cards

Credit cards can be used to slip between locks thus opening the door. It’s not as clean a process as you see on the TV so check for bits of plastic that might have broken off from the card in the attempts to open the door. Other cards can also be used such as gift cards, membership cards and even bits of plastic cut from soda bottles.  See if anything like this is lying around outside your door or on your walkway. A deadbolt cannot be unlocked using a credit card. Only doors with hinges on the opposite side of the door and those with a latch that slants facing you can be opened with a card.

To prevent someone from picking your lock you could look at installing an electric strike plate to your outside door.  This would eliminate the need for a key, thus preventing any burglar from picking your locks!

2. Signs of Breaking Through the Door / Frame

The sturdy burglar might well try this method if no one is in the vicinity to see him. This method of breaking in is obviously going to require some force and you’ll be able to see immediately that someone has entered through your door! Crowbars, pipe wrenches or just a pair of well booted feet can be used to break through a door. Some intrepid burglars even use power drills to get through the deadbolt.

CrowbarTake a look at the frame of the door and see if you can find splintering or bending that would indicate someone has tried to kick in the door.  Look for scuff marks on the paint or bits of mud or dirt left behind by the intruder’s shoe.

Check the edges of the door for signs of tampering.  This is the weakest part of the door because it is where the bolts go through to lock the door into the frame. The bolt and latch don’t distribute force very well so if your doorframe is reinforced, the edge will be damaged if someone is trying to kick the door open.

To prevent this type of entry from occurring reinforce your doorframe with a layer of steel to prevent the wood splitting. High-gauge steel should be placed over the door jamb and be secured with long screws that penetrate right through to the studs. Install a door wrap around the door to reinforce the edge.

Now, take a look at the hinges of the door.  Are there any signs that someone has tried to remove the door from its hinges? Exposed hinges are not common in the home but can be seen on commercial building doors.  See if there are any scuff marks around the hinges or chips of metal or disturbed paintwork. If you think someone has tried to gain access this way you can install jamb pins to reinforce the hinges.

Lastly, examine the strike plate of the door. If it looks like the strike plate has been bent or damaged in anyway, it’s a sure sign someone has tried to gain illegal entry. You can make your strike plate stronger but removing the old screws and replacing them with longer 3-inch screws. You could also replace the strike plate with a longer one – which means that more screws are needed to secure it into place which in turn means that it is harder to damage.

3. Signs of Using the Door Handle / Knob

A lot of people don’t lock their front door making them easy targets for burglary. Someone might simply walk by your home and opportunistically try the handle of your front door. This might not be an easy thing to spot but if you notice that the shiny handle you left behind in the morning is now looking a bit dirty, it might mean someone has entered your house uninvited. Or you might be lucky, and the thief’s fingers were a bit greasy when he opened your door, and he has left behind a fingerprint.

If you suspect that someone is habitually trying to gain access this way, here is a little tip you can try:

  • Talcum Powder Trick – When you go out, lightly dust the door handle with talcum powder. If someone tries to open the door while you are out, you’ll be able to see the fingermarks left in the powder.
  • Sneaky Hair or Paper Trick – Make a small mark on the doorframe with a pencil, stick a hair across the door on the mark you have just made. If the hair is not there when you return, you know someone has opened the door. The observant thief could possibly see the hair and then replace it once he leaves the house, however, it is unlikely that he will place it on the small mark you have made. So, if the hair is out of place, it is another sign of entry. You can do a similar thing with a piece of paper. Mark a spot on the doorframe and jamb a small piece of paper between the frame and the door – if the paper is gone or in a different spot when you get home, you know someone has opened the door.
  • Clear Tape Trick – You could stick a bit of clear tape on the closed door covering part of the door and the doorframe. If the door is opened the tape will come loose. Most burglars will not notice clear tape in their hurry to get in and out of the house as soon as they can.
  • The Boot Trick – Take a pair of shoes and place one shoe a little way behind the door. As you leave the house place the second shoe behind the nearly closed door. If someone opens the door it will push the second shoe next to the first one. No one will suspect anything of a pair of shoes sitting near the front door, but you will know someone has entered your house if you see the shoes together.

The most obvious way to prevent this type of entry is to simply make sure all outside doors are locked before you leave the house.

4. Signs on the Outside

PorchThere might be no visible evidence that your door has been opened but there might be some signs in the environment surrounding the door.

You might notice dirty footprints on your porch or possibly a pot plant that has been knocked over. Anything that looks out of the ordinary on the porch or walkway might indicate that someone has tried to get into your house through the front door.

If it’s winter and you live in an area where snow falls, you might see strange footprints in the snow leading up to your house. You can take this as evidence that someone has tried to get into your house.

If you notice a strange vehicle parked in the street outside your house, take care as you enter your house, it might be that someone is in your home.

5. Signs on the Inside

Again, if there are not many clues to be seen on the door itself and there is no evidence in the surroundings, take a careful look around inside the house.

  • What do you see?

It’s unlikely that you would have left lights on when you went out of the house – especially if you left in the morning, so, if you come home and a light is burning, it’s a pretty clear sign that someone has been in your home. If it’s been raining outside there might be wet footprints in evidence on the floor of your vestibule. See if anything else is out of place – ornaments that aren’t where they should be or pictures hanging skew.

Like Goldilocks in the classic fairytale, some intruders can start to make themselves feel at home in your home – especially if slightly intoxicated. Check to see if someone is passed out or asleep either on the couch, the bed, or even the floor. They might have removed food from your refrigerator so check that all your perishables are still in place.

  • What do you hear?

Don’t just keep your eyes open, keep your ears open too! If you have that funny feeling that someone has opened your door and entered your home, listen carefully for sounds that are out of the ordinary. Regular patterns of movement could mean that someone is moving up or down stairs. You could hear a door or floorboard creak or the sound of something breaking.

If your house is alarmed, you should be able to hear the siren sound while you are still some ways away from your house. If the alarm has not been triggered but you suspect entry, check to see if it has been bypassed or if any wires have been cut. Research has been done to suggest that some wireless alarm systems can be subverted so that the alarm is suppressed, or false alarms created so that the alarm system is rendered unreliable. Burglars can use a simple tool to set off false alarms. This can be from as far away as 250 yards. Closer proximity is necessary to disable the alarm entirely.

Tips to Stay Safe

So now you know what to look for to tell if your door has been opened.  But what now?  How can you prevent this? A few things have already been mentioned above – installing an electric strike plate, reinforcing the door and/or doorframe, and simply locking the door behind you can all prevent a break-in – but there are a few other things you could do too.

Remember to check all your outside doors for signs of entry and if you have a garage door that connects directly to the house, treat this door just as you would an outside door – use the same locks and reinforcing materials.

Before leaving home take a look around and note the condition of the house. Take note of the placement of various ornaments, books, chairs, etc.  When you get home, you then have benchmarks to work with to be able to see if anything is out of its place.

Make sure you have a plan set up for if you experience a break-in. Set up a meeting spot for your family where you can all meet in an emergency. This could be a neighbor’s backyard or a nearby play park.

Make sure your family knows how to exit your house quickly and effectively in the event of an emergency.

Lock your doors!  Lock them when you leave the house and when you go to bed at night. If you are in an area of high crime, you might think of installing a security door. Some other things you can look at installing are:

  • Smart Sensors – These sensors will pick up when a door (or window) is opened and will send a notification to you via your smartphone. A log is made, and the date and time are recorded so you know exactly when the door was opened. Take a look at these on Amazon. They might be just what you’re looking for.
  • Security Gates – Although these might be a bit of an eyesore, they will add an extra layer of security to your outside doors. They are made of steel and will definitely stop a door from being kicked in and if you have left your door unlocked, the potential thief while being able to open the door, still wouldn’t be able to gain access to your house.

To prevent the loss of precious items in your home, keep them locked away if you are going to be away from home for an extended period. Keep cash and mobile phones on your person.

Some Questions People Ask

What do I do if I think someone is inside my house?

If you think someone is in your home or you see signs of forced entry, don’t enter the house. Call the police immediately. If you have entered your house and noticed signs of a home invasion, exit as soon as you can and call the police. Go to a neighbor’s house and wait until the police arrive.

If you are inside the house and find you cannot leave easily, lock yourself into a secure room. Don’t come out until the police arrive.

It is a good idea to keep the police’s phone number on speed dial on your phone in case of emergencies.

If I think someone is in my home, should I call out?

Most intruders want to avoid confrontation so if you think someone might be in your home, call out “Is someone there?”  Maybe call out the names of family members to check it isn’t one of them. If you make your presence known, it is likely that the intruder will make a speedy exit through another door or window. Another way to frighten a burglar is to set off your car alarm – the noise will alert them of your presence and hopefully, they will run away.

What do I do if I am inside my house when an intruder comes in the front door?

If someone enters your house, try to get to a safe room where you can lock yourself in and call the police.  If you are unable to get to a room, try and keep hidden.  Don’t make a noise and try to avoid any confrontation.

What do I do if an intruder sees me?

If a burglar sees you, the best thing to do is to cooperate with him.  Do as he says and give him what he asks for.  Don’t try and be a hero!  Let him take what he wants without threat and once he has gone, call the police.

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