5:56 PM PT -- Polo’s lawyer Bradford Cohen tells TMZ … regarding the Burbank arrest, "We are waiting [for] additional information. The charges against Polo are very unusual given the timing and alleged knowledge of the police."
He continues, "We believe once all the facts come out it will be a very different picture than how the charges look on paper. We look forward to challenging the accusations and vindicating our client."
Polo G and Trench Baby's arrests ended with them both getting booked for crimes -- the rapper for gun possession and his brother for robbery.
LAPD says Wednesday's raid at Polo's house was in response to a report from August 15, which alleged Trench Baby robbed a man in Granada Hills during a music video shoot.
The alleged victim arrived on location to film the video, and cops say Trench Baby drew a handgun with an extended magazine, demanding the man empty his pockets and wire money to him into another account.
According to cops, Trench Baby and the alleged victim had a prior working relationship. When officers made the arrest, they say they found a small baggy of unknown drugs on Trench's person during a pre-booking search.