TMZ is reporting that Bubba, a dancer for Cali Swag District who is best known for his heavyset shirtless "Dougie" in their 'Teach Me How To Dougie' video - was a witness to the drive-by shooting that claimed the life of 22 year-old CSD rapper M-Bone early Monday morning in Inglewood, CA.  According to TMZ:

Several witnesses tell us Bubba was waiting inside of the car M-Bone drove to the store ... and when the fatal shots were fired, shards of broken glass struck Bubba in the face. Witnesses also tell us M-Bone was shot as he tried to get inside of the car.

Bubba was hospitalized for his wounds -- though we're told the injuries are not life-threatening.

TMZ also reports that M-Bone was being threatened by a man who was jealous of he and Cali Swag District's success - this, according to M-Bone's live-in girlfriend.  Sources among M-Bone's friends tell TMZ that the man was also jealous of the new relationship with the girlfriend, who M-Bone reportedly had recently gotten involved with after the Blizzard Music Tour recently wrapped up.

Apparently M-Bone and the unidentified man have been involved in a Twitter war recently, and the  man, who lived in the same apartment complex as M-Bone and his girlfriend, had been "overtly hostile" and made violent threats lately.

From TMZ's discussion with M-Bone's girlfriend (who is scared and chose to remain anonymous):

The girlfriend tells us ... on Sunday ... she picked M-Bone up at the airport at 12:15PM and took him back to their apartment. Later that night, at around 10PM, M-Bone took her car and said he was going to the studio to record.

She tells us soon after she got a call from another member of Cali Swag with the devastating news her boyfriend had been shot.

As we first reported, the gunman fired shots as M-Bone stood near his girlfriend's car which was parked outside an Inglewood, CA liquor store. The shooter drove a short distance, then made a U-turn and came back, presumably to see if he had hit his target.

KISS-FM will continue to keep track of this story as police search for M-Bone's killer.

Check out photos of M-Bone at Cali Swag District's March appearance in Casper, plus photos and videos from their time backstage with KISS VIP's.