@sandraenglandlondon - you are a bit off topic. your comment doesn't help. 
Maybe I didn't make it clear. Most petty crimes are here are done by people who actually know others. You befriend some locals, they have this perception that westerners are all loaded so its okay to steal from them. Also they know foreigners don't have a leg to stand on when it comes to complaining to the authorities - no judicial review either.