Whether you’re trying to prove your roommate has been “borrowing” your clothes or you’re just looking for a home surveillance solution, the following Mac app will have you covered.

Witness will turn your Mac’s iSight camera into a motion sensor that begins recording when it detects any activity within its line of sight. If it does pick up some movement, the app will then immediately alert you through its free iPhone or iPad app. And the alert is coupled with images and video of the intruder.

Orbicule, the developers of Witness have designed the app to eliminate recording hours of uneventful footage and it also saves you from wasting precious bandwidth. While operating Witness remotely from an iOS device, users can activate or turn off the alarm in addition to receiving a notification that something has triggered the camera.

When the alarm is activated, Witness will capture approximately 15 seconds of video and will automatically upload the footage to Orbicule’s servers while sending a push notification to the iPhone or iPad.

laptop thief Witness: Turn your Mac into a motion detector surveillance tool

There’s no limit to how many Witness-enabled Macs you can have running and after the alarm is turned on, all Macs will have the ability to send alerts. Users do however have the option to exclude any one of the Macs by configuring Witness on Orbicule’s site.

Third-party cameras aren’t technically supported, however Orbicule mentions on its site that if a cam works in PhotoBooth, iChat or FaceTime, it should work with Witness as well. If a thief attempts to steal your Mac, unfortunately you won’t be able to track it although it does support the Mac OS X screensaver password feature as well as its own built-in lock screen. Orbicule doesn’t offer a free trial for its $39 Witness app but they claim users can request a full refund within 30 days of purchasing.