The FBI seems like the least careful of all the agencies penetrating computers. NSA > Secret Service > CIA > FBI

They're either messing up an investigation or destroying their public image.

1) Accidentally resetting the Bernadino terrorist's iCloud password

2) Withdrawing its demands from Apple after significant backlash

3) Asking for the ability to inspect browser history without a warrant

4) Modifying the computers they're "lawfully" allowed to breach - can we trust this evidence in court?

Wouldn't trust them with more authority that's for sure.