The 18-year-old Virginia man suspected in the slayings of three family members exhibited warning signs before the incident, according to his uncle.

Bryant Bernard told WSLS his nephew, Matthew Bernard, admitted to his mother, 62-year-old Joan Bernard, that he had been experiencing nightmares just one week before police say he killed her, his sister, identified as 25-year-old Emily Bivens, and his toddler nephew, Cullen.

"He expressed to his mother last week that he was having bad dreams, and that he'd seen demons around his bed," Bryant Bernard told the station.

"He woke up [on Tuesday,] he said something to his mother that something's going on and 'it has to stop today' and he left," he added, about the day of the triple homicide. "They never saw him again until the point of where [his mom] got back home and that's where she confronted him."

9 PHOTOS Matthew Bernard arrested in slayings of mother, sister and 1-year-old nephew See Gallery Matthew Bernard arrested in slayings of mother, sister and 1-year-old nephew This photo made available by the Pittsylvania County Sheriff shows Matthew Bernard on Wednesday, Aug. 28, 2019. Authorities said Bernard is charged with three counts of first-degree murder. Pittsylvania County Sheriff Mike Taylor indicated he's related to the victims. (Pittsylvania County Sheriff Office via AP) Matthew Bernard is charged with three counts of first-degree murder in the slayings of his sister, identified as Emily Bivens, the pair's mother and Emily's toddler son, whom she had with husband Blake Bivens, a minor league pitcher for Tampa Bay Rays affiliate team the Montgomery Biscuits. Bernard led police on a massive manhunt while fully nude on Tuesday. Blake Bivens, pitcher for the Montgomery Biscuits. Emily and Blake Bivens The toddler son of Emily and Blake Bivens, who just celebrated his 1st birthday on June 10. Blake and Emily Bivens on their wedding day. (Photo: Facebook/Emily Bivens) (Photo: Facebook/Emily Bivens) (Photo: Facebook/Emily Bivens) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Police responding to the family's home in Keeling, Va., near the Virginia-North Carolina border, discovered one of the adult female victims dead in the driveway of the home and the other adult and baby Cullen dead inside.

The youngest victim, who turned 1 in June, was the son of Emily and her husband, Blake Bivens, a minor league pitcher for the Montgomery Biscuits, a Tampa Bay Rays affiliate team.

A massive manhunt ensued, with dozens of officers searching a nearby wooded area for the suspect, who fled the scene on foot. Multiple area schools were placed on lockdown, including Danville Community College, where Bernard was a student.

Around noon, the suspect reemerged from the woods fully nude and led police on a brief foot chase, attacking a church groundskeeper before he was eventually subdued by officers and a K-9 unit as he ran back toward the scene of the crime.

Immediately after he was placed in the back of a police cruiser, Bernard reportedly began bashing his head against the cage between the front and backseat, resulting in an injury, which is visible in his mugshot, WDBJ reports. He was taken to Carilion Roanoke Memorial Hospital to receive treatment before being transferred on Wednesday morning to Pittsylvania County Jail, where he was placed on suicide watch.

Pittsylvania County Sheriff Mike Taylor described the case as particularly upsetting as authorities work to figure out a potential motive in the brutal killings.

"It's devastating," he said. "It's something you don't get used to."

The Montgomery Biscuits canceled a scheduled doubleheader Tuesday in Chattanooga, Tenn., over the tragedy affecting its team member.

"Earlier today we learned that Blake Bivens, a pitcher with our Double-A affiliate, the Montgomery Biscuits, suffered a terrible family tragedy in southern Virginia," Lou DiBella, the team's CEO & managing owner, said in a statement. "Our hearts are broken for Blake."

A GoFundMe has been started by friends of the Bivens family to cover the cost of Emily and Cullen's final expenses.

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