Burglar
Often, your house will be infiltrated by a burglar, who will rush round your house cramming items the size of television sets into a small black bag. Burglars only appear if every Sim in the house is fast asleep, and can easily be prevented by installing a burglar alarm at every door. If one is installed and a burglar still attempts to rob you, the police will come running, attempt to arrest the burglar and if successful offer you §1000, as well as being reimbursed for anything the burglar may have stolen. The police will ask to keep the stolen items for evidence. If you don't have an alarm, you can call the police, but the police never make it on time meaning you never stop the burglar and never get the award and they simply run off with your Sim's possessions.
In The Sims 2 some sims, particularly fortune sims often have "getting something stolen" as a fear. It is possible for the police to catch the burglar if you call them quickly enough.
In The Sims 3 the Criminal career track is available, a burglar is a possibility.
Tips
An exploit to burglar proof your house that works in both games is to make a single wall on both sides of the street and put an alarm on them, causing the alarm to be set off as soon as they appear on the lot. Its also an easy way to randomly make 1000 Simoleons, especially if you make sure all of your Sims go to sleep at the same time.
Safe Proof your house by putting a burglar alarm on the front door back door and on each space on the entrance to the lot!!
To kill a burglar, you need at least one of the expansion packs. Type the boolProp cheat (boolProp testingCheatsEnabled true). Then Shift Click on the victim (hopefully the burglar), and click make selectable. You need to typeyour cheat while in the neighborhood for it to work. Then, just drag his hunger meter ALL the way down. He will die shortly. Also, if you want to laugh while he dies, you need either Nightlife or Open for Business. Go to simwardrobe.com, click The Sims 2, then click objects, then Shooters! then assault rifle.
If you want your house totally burglar-proof, here's what you do. (This works for both The Sims 1 and 2.) Delete all of the doors that lead from outside to inside. Also make sure all fences and other doors that lead to your house are deleted as well.
--One common burglar is Russ Bear.