I’m gonna make the assumption you live in the United States.

Anyone who steals something from inside your car Are typically opportunistic. Yes, there are people who make a living out of stealing cars and they make a living out of stealing parts of cars, but those guys tend to target particular vehicles and Particular parts ….tend to…

You said the alarm didn’t go off are you sure you didn’t accidentally leave the car unlocked?

Ways to prevent theft from your car:

• Always lock it
• Always park under lights
• Don’t leave anything of any value in the car that’s visible from the outside. If you have to leave valuables in your car, put it in the trunk
• If you can park your car in a garage
• Even putting a car in a parking lot that has some degree of perimeter fencing will deter thieves.
• Make sure the doors and windows all work properly. This may be obvious, but if you have a missing window, it’s an easy access or if you have a door that doesn’t lock properly, etc. etc.

Ways to respond to theft from your car.

• Report it to your insurance company
• Report to the local police department
• If you live in an apartment building reported to the landlord
• If you have things like a third-party GPS or other equipment in the car, keep the serial numbers and descriptions of those things in a folder in your house. My car got broken into you once in the The thieves stole my GPS. They cleaned out my change. I’d left some jewelry in the car. They cleaned that out. I reported all the police with the serial number and amazingly they recovered the GPS.

Finally car alarms are a waste of time.