They're licensed to carry firearms.
4 seconds sound clip from the The Godfather (1972) movie soundboard.
You can hear this line at 01:10:10 in the Blu-ray version of the movie.
Quote context
[...]
- What's the Turk paying you to set up my father, Captain?
- Stand him up. Stand him up straight.
- I'm the attorney for the Corleone family.
- These men are private detectives hired to protect Vito Corleone.
- They're licensed to carry firearms.
- If you interfere, you'll have to appear before a judge in the morning and show cause.
- All right, let him go. Come on.
- What's with all the new faces?
- After the hospital thing, Sonny got mad.
- We hit Bruno Tattaglia at 4:00 this morning.
[...]