Lil Wayne Investigated for Assault ... AGAIN!!!

For the second time in a month, Lil Wayne and his entourage are under investigation for assault ... and once again the alleged victim caught a beatdown for daring to take a photo of Weezy.

Alfredo Marino tells TMZ on May 3 he spotted Lil Wayne and his posse skateboarding. Marino says he is a HUGE fan of Wayne's so he went up to Weezy to ask for a photo -- but was shut down.

Marino retreated to his car, where he tried sneaking a pic  ... Marino claims Wayne walked over with his crew and began threatening him, saying, "Don’t you know all it takes is a word and these motherf**kers are going to f**k you up?"             Full Read