50 Cent Jeweler Says Rapper's Crew Brutalized Him

50 Centis smack in the middle of a criminal investigation after a guy claims 50's goons pistol whipped him and stole a quarter of a million dollars in bling.

 
Robert Marin, who owns LAX Jewelry Co., tells TMZ he went to Vegas during fight weekend because he wanted to sell the rapper a watch and chain worth $250K.