The wife, child and mother-in-law of a minor league baseball player were allegedly killed in southern Virginia on Tuesday by the player's brother-in-law, according to the sheriff and a report.

Matthew Bernard, 18, was apprehended while running around naked following an hourslong manhunt after police discovered the bodies of Emily Bivens, her son Cullen and her mother.

Emily was married to Blake Bivens, a Double-A pitcher in the Tampa Bay Rays organization.

ESPN was the first to report the relationship, and Pittsylvania County Sheriff Michael W. Taylor confirmed Wednesday that the victims are related to the baseball player.

He identified the victims as Bernard’s mother, Joan Bernard, 62; Matthew Bernard's sister, Emily Bernard Bivens, 25; and Cullen Bivens, 14 months old, who is the suspect's nephew. Bernard is charged with three counts of first-degree murder, but Taylor said a motive is still unknown.

The Montgomery Biscuits, the minor league affiliate of the Rays, canceled its double-header Tuesday, alluding to a "tragedy" that had struck their community. Later that evening, the team put out a statement expressing their sympathies for Bivens.

Blake Bivens throws a pitch during a MiLB game between the Dayton Dragons and Bowling Green Hot Rods in Kentucky in 2016. Steve Roberts / Cal Sport Media / AP file

"The Biscuits thoughts and prayers are with Blake and all those who have been impacted by this tragedy," the team wrote.

The Tampa Bay Rays also mourned Bivens' loss on Twitter.

Police learned of the murders Tuesday morning when a neighbor reported that someone may have been shot. When officers arrived, a deputy found a woman dead in the driveway of a home, Pittsylvania County Sheriff Michael W. Taylor said at a news conference Tuesday afternoon.

The deputy found two other victims inside the home and called for help. More than 100 officers from several law enforcement agencies were involved in the search, which ended with the suspect's arrest shortly after noon, he said.

Bernard is being held without bail and is on suicide watch, Taylor said.

He was treated and released from a hospital because he banged his head against the cage of the police vehicle after his arrest. Taylor said he did not know why Bernard had no clothes on.

Bernard's uncle, Bryant Bernard, told NBC affiliate WSLS of Roanoke that his nephew was taken into custody and was accused of killing his mother, sister and her child. NBC News reached out to the family for comment.

"In my wildest dreams, I never could have imagined it. Not him. Of all the people in this world. I never could have imagined it," Bryant Bernard said of his nephew to WSLS. Bernard confirmed the names to the affiliate.

Taylor said Wednesday that a firearm was involved in the incident, but would not say whether a gun was recovered or what kind, citing the investigation.

All three victims lived in the home in the community of Keeling, Taylor said.

Taylor said that he met with Blake Bivens and his family, and called the tragedy "a horrible thing for this young man and his family to go through."

"I can't speak for him. I do know his family," Taylor said. I think that he has questions, just like we all do at this point — questions that we couldn’t answer last night. And hopefully as we get through this investigation we will be able to bring those, or to answer those questions."

Several schools in the area were locked down during the search for the suspect.

"This was a shock to our community — to anybody's community, when something like this happens," Taylor said Tuesday.

CORRECTION (Aug. 30, 2019, 9:20 p.m.): An earlier version of this article misstated the age of the suspect, Matthew Bernard. He is 18 years old, not 19.