POORSTACY's Baby Mama & Child Were in Room During Rapper's Suicide, Police Say

POORSTACY's baby mama has been arrested ... with cops alleging drug use in the presence of the couple's young child in the days before the rapper's death ... and we're learning she and the kid were in the room when the musician killed himself.

Nicole Grikstas was arrested Saturday hours after POORSTACY -- real name Carlito Milfort -- took his own life ... with cops booking her on a child neglect without causing great bodily harm charge.

According to a Boca Raton Police affidavit -- which cites an interview conducted with Nicole at the police station hours after the rapper was found dead in a hotel room -- cops say Nicole broke down the events leading up to his death by handgun.

Nicole told police the couple and their child checked into a motel in Boca Raton, Florida a week before his death ... where the couple allegedly consumed copious amounts of drugs in front of the child. She told officers the two were using cocaine, MDMA, and Xanax while staying at the motel.

Cops say Nicole told them she and Milfort arrived back at their hotel room around 11 PM Friday, Nov. 8 ... where they both took some cocaine. Cops say Nicole told them a few hours later -- around 3 AM -- she took a dose of MDMA.  Nicole told officers she and Milfort argued frequently throughout the night ... accusing each other of infidelity. Police allege Nicole did not try to remove their child from the explosive environment.

Nicole told cops Milfort accused her of hiding his drugs -- she denied doing so. She told police he forcibly removed her clothing in order to check her vaginal and anal areas for hidden narcotics ... before striking her multiple times.

At this point, Nicole told police Milfort pulled out a gun and threatened to shoot her if she didn't tell him where his drugs were ... alternating between pointing the gun at himself and her over the next hour -- before she says he put the gun to his head and pulled the trigger early Saturday morning.

Officers responded to a 911 call from the front desk ... they searched the motel room and observed drugs and drug paraphernalia, children's toys and food strewn around the room ... as well as the loaded Taurus handgun.

Cops say after the interview and the search, they determined she and Milfort exposed their child to numerous drugs over their stay ... they say she made no attempt to remove the kid while Milfort was waving around the the gun.

A source close to the Milfort family tells TMZ … Nicole’s family currently has the child.

We broke the story ... police determined POORSTACY's death was a suicide -- though members of his family don't believe the official claim and believe it may be foul play.

We've reached out to Nicole's parents ... so far, no word back.