Rapper POORSTACY'S Cause of Death Revealed, But Family Disputing It

Rapper POORSTACY's death in Florida was a suicide ... TMZ has learned, but some of his family members feel it was something more nefarious.

Multiple sources with knowledge of the investigation tell us POORSTACY shot himself Saturday morning in a Boca Raton hotel room, but initially survived. He was transported to a local hospital, where he died Monday, after being taken off life support.

Police have yet to officially release the cause of death, but we're told the rapper's family isn't buying it was suicide. One source connected to his family tells TMZ ... the family is disputing it was a self-inflicted gunshot wound ... and they suspect foul play.

We're told POORSTACY had been staying at the hotel for about 10 days, after checking in with a woman and a toddler. Our source says POORSTACY was the child's father, and the woman is the mother.

It's unclear if they were in the hotel room when he shot himself.

We're told police released the room back to the hotel later Saturday to be thoroughly cleaned.

We broke the story of POORSTACY's death, and at the time, there were unconfirmed rumblings it might have been suicide.

Sadly, that's what police believe happened to the 26-year-old artist, according to our sources -- but it sounds like his family members might demand further investigation.