BRONX, N.Y. — Though officers chalked his death up to a seizure during a drug arrest, a Bronx mother claims in court that her son died after being left handcuffed in a police van with the heat cranked up.

Johnathan Jennings, 19, died on the early morning of March 31, 2016, after the New York City Police Department busted into his home on suspicion of marijuana and cocaine possession.

Anonymous police sources told the New York Post at the time that the teenager suffered a seizure, but the mother, Monica Davis, contradicted that account in the New York Daily News.

Davis told the paper at the time that her son did not get seizures and had a clean bill of health apart from a minor issue with asthma.

“Davis also said witnesses told her that her son was roughed up by police in the van, and that he sat in the van for at least 45 minutes, was sweating profusely, and bleeding from the mouth,” the tabloid reported.

On Thursday, Davis took those allegations to Bronx County Supreme Court.

Though thin on details, the 15-page complaint claims that the NYPD “tortured” Jennings by “placing him, while in handcuffs, in an enclosed police van and turning on the heat to an excessive degree for an excessive period of time.”

Sgt. Keith Geller and unknown officers from the Bronx’s Narcotics Unit at the 48th precinct of having “beat, assaulted and utilized excessive, unnecessary and brutal force” without provocation, according to the lawsuit.

While no details have been reported about Jennings’ autopsy, the lawsuit states the teenager suffered “seizures, cardiac arrest, respiratory failure, bleeding, lacerations and/or bruising.”

The family’s attorney Susan Davis, who shares a name with the mother but is not related to her, declined to comment.

The complaint seeks damages for three counts of negligence, wrongful death and a pattern and practice of civil rights violations.

A spokesman for the New York City Law Department said the city will review the complaint.