REPORT: Heroin Found On Nelly's Tour Bus . . . Was For 'PERSONAL USE'!!!

Rapper Nelly was detained last night in Texas while police officers searched his tour bus -- and found HEROIN in addition to a loaded gun ... and MASSIVE amounts of weed ... law enforcement sources tell TMZ.

According to law enforcement sources, Nelly's bus was stopped at a border patrol checkpoint in Sierra Blanca -- and a police canine detected the presence of drugs.

We're told cops pulled the bus over -- and after performing a search, they found 36 small baggies of heroin (totaling .64 ounces) and over TEN POUNDS of marijuana inside a large green duffel bag (an amount roughly the size of a large bed pillow).

Cops also say they found a loaded .45 caliber pistol.

Now police say that one of Nelly's FRIENDS ON THE BUS copped to the drugs and the gun. So Nelly is NOT being implicated in it.But here is the INTERESTING PART. Reports say that the man arrested claimed that the HEROIN . . . was for the PERSONAL USE of the people on the tour bus.
OOOOH SH*T!!!   TMZ/M.T.O