Cops say Aaron Hernandez's brother, Dennis "D.J." Hernandez, experienced a bipolar episode less than three weeks before his ESPN arrest ... one that resulted in a wild police chase through Connecticut roadways.
It all allegedly went down on March 8 -- just 15 days before he was accused of hurling a brick at ESPN's headquarters in Bristol -- when cops say they attempted to stop D.J. in his silver Hyundai as he was driving through Cheshire.
According to the Cheshire Police Department, D.J. was driving erratically and at high rates of speed -- at one point traveling through grass fields in front of the Cheshire Correctional Institution.
But, police say when they attempted to pull him over ... D.J. blew through a red light and lost officers.
According to police documents, obtained by TMZ Sports, cops made contact with D.J.'s mother -- Terri Hernandez -- a short time later ... and they say she told them the 36-year-old former UConn football player had "been acting very strange and she believed he needed to be mentally evaluated at a hospital."
Eventually, police documents show, the Bristol Police Dept. was able to take D.J. into custody "after a brief foot chase." Cops said in the docs D.J. was having a bipolar episode ... and told them he had been driving all over Connecticut trying to get arrested because "he no longer wanted to stay at his mom's house."
Cops say he was committed to the Bristol Hospital on a Police Emergency Examination Request.
D.J. -- who changed his name to Jonathan after Aaron's murder conviction -- was ultimately hit with five criminal charges over the incident, including reckless driving and engaging police in pursuit. He's due in court for a hearing on the matter in mid-April.
As we reported, on March 23, just over two weeks following the March 8 incident, D.J. was arrested again after he allegedly threw a white bag that contained a brick and a handwritten note at ESPN's campus.
He's facing a charge of breach of peace in that case -- with a court date slated for early April.