The Virginia madman accused of killing his mother, sister and 14-month-old nephew was put on suicide watch ahead of his initial court appearance, which was canceled after he was rushed to the hospital early Thursday for an “undisclosed reason,” according to a report.

Matthew Thomas Bernard — the 18-year-old brother-in-law of Blake Bivens, a pitcher for the Tampa Bay Rays’ Double-A affiliate, the Montgomery Biscuits — was scheduled to appear in court for the first time early Thursday, but the hearing was abruptly canceled due to an unknown medical issue, WSET reports.

Bernard initially was hospitalized after being taken into custody while running naked Tuesday through Keeling, Va., where authorities had found the bodies of Emily Bivens, 25, Joan Bernard, 62, and 1-year-old Cullen Bivens hours earlier, Pittsylvania Sheriff Michael Taylor told reporters at a news conference Wednesday.

Cops said Bernard was banging his head against the cage of a police cruiser after being arrested and was released back to the sheriff’s office at 3 a.m. Wednesday following his hospital visit. He has since been placed on suicide watch, Taylor said.

A motive in the slayings remains unclear, but a firearm was “involved in the incident,” the sheriff said.

A criminal complaint obtained Thursday by WSET shows that a neighbor of Bernard’s told police he came to her house early Tuesday and punched her in the arm. She later heard several gunshots coming from the family’s home, where she found the body of Joan Bernard in the family’s driveway.

A responding deputy found the bodies of Emily Bivens and her son inside the home with visible gunshot wounds to the head. A rifle was recovered from behind the residence, while spent shell casings were discovered near the bodies of all three victims. A sledgehammer covered in blood was also found in the garage, according to the criminal complaint.

Deputies were alerted during Tuesday’s manhunt that Bernard — Blake Bivens’ brother-in-law — was armed and “very” dangerous, leading a nearby community college where he attended to be locked down. Bernard is also accused of killing the family’s dog.

He remains held without bail on three counts of first-degree murder in the Pittsylvania County Jail ahead of what was to have been his initial court appearance Thursday, WSET reports.

Bernard had been battling mental health issues prior to the slayings and snapped after reaching a “breaking point,” according to his cousin, Jenn Stallard.

“Unfortunately he was suffering with mental illness and came to a breaking point,” Stallard told DailyMail.com. “Matthew is my cousin and I will love him and be there for if I am ever able to because what the public has seen was not him at all and his family, we would never imagine this could have happened.”

Bernard attended Danville Community College and worked at his family’s campground, according to court documents cited by WSET.

But cops said he was in “obvious mental distress” when they couldn’t subdue him with batons and pepper spray while trying to arrest him. He ultimately was collared with help from a police K-9 and two state troopers, according to the station.

Bernard is now scheduled to be arraigned on Sept. 5, the Danville Register & Bee reports.

With Post wires