I have finished my degree in computer science with a specialization in telecommunications engineering, and I wish to join an intelligence agency and do computer work. However... I did a somehow negative act in my late teens. 

I, along with a close friend of mine, decided that it would be a good idea to have digital access to the school administration by sneaking into the school on a Saturday night and installing a program that would send us activity logs (basically every key they press during the entire day) at 9 PM every day.

Everything went as normal, and we went to school for the next week, but then a police report was filed by an off-duty custodian who caught us trespassing and probably saw the lights of the computer screens as he shadowed us inside. The police never confronted me or my friend about this.

Any IA that I would apply to will have access to and will definitely open to see this police report. I don't know if this would be seen as a serious offense, or how strict they are on these matters. For a moment I thought they might even find it amusing, but I know that people are very easily brushed off if they have the smallest prick.