Difference between Lay a finger on someone and Put the finger on someone

lay a finger on someone—(also: set a finger on someone) touch or harm a person however slightly:

• I never ever laid a finger on him. We were very good friends.

put the finger on someone —(sl.) inform against smb.; denounce a person to the police:

• If I’m grabbed with this junk I’ll rot in jail before I put the finger on you.