What secret trick does law enforcement have that civilians don’t know about?

Resisting arrest trick
if a police officer Wants to arrest you can see you might be committing a crime, say stop resisting arrest a couple of times and then, that could be the only charge against you.
If a police officer wants a report from you say you don’t recall, otherwise he can use his interpretation of events against you and testify against you on charges you might not even have committed.
Using your friends or family against you, just because you use safe practices doesn’t mean your family members do and can hold charges against you family member.
Bugging your house and car, hacking your phone and computer, gps tracking you via your phone and car.
Can get away with killing people
Joshua Brown, Witness in Amber Guyger Trial, Was Killed in a Drug Deal, Police Say
So unless you know where the police officers kids go to school don’t testify against a police, and have people ready to kill them. I don’t condone killing of police officers kids.