[Doctor Stochastic]

Quietly report it to the police. Calmly explain to them what is happening. Tell them someone is leaving time delay improvised explosive devises in your neighborhood.

The best suggestion so far.

[Alberta's Child]

There's one big problem with reporting something like this to the police. If you report it and they don't do anything about it, you may have to take matters into your own hands sometime down the road. And the fact that you reported it will make you a prime suspect for the police if they get involved later.

I know what it's like to be a "young punk," and believe me -- the people we feared the most were the ones who never called the police.