What's "running a check" mean?
SCRIPT
Mike: "It's the suburbs. I didn't think it'd matter. Anyway, the police are running a check, and I'm in the system.

QUESTION
1. What does "run a check" mean?

2. What does "I'm in the system" mean?

Of course it's easy to figure their meaning out but I just want to make them clearer. Thank you so much!

Question

What's "running a check" mean?
SCRIPT
Mike: "It's the suburbs. I didn't think it'd matter. Anyway, the police are running a check, and I'm in the system.

QUESTION
1. What does "run a check" mean?

2. What does "I'm in the system" mean?

Of course it's easy to figure their meaning out but I just want to make them clearer. Thank you so much!

Answer

The "system" is their computer system, and the police are performing an inquiry using it.

Answer

If you are in the system it means that you have been arrested or have had to pay a fine previously. It may include your arrest/conviction/criminal record/outstanding fines as well as  fingerprints. If the police are running a check then they are usually checking to see if you have a criminal history.