Weeping and shaking, his mother, Olgie Maynard, confirmed as much, saying her son was institutionalized for about a week three to four years ago.
"He went crazy," Olgie Maynard told CNN, explaining her son hadn't been the same since he was involved in a workplace explosion five or six years ago in Alabama. "He was out in the yard yelling. We called the police, and they took him away."
Since then, she said Tennis had gotten more psychiatric help at another mental health center. At home in Ragland, where he lives with his parents, he mostly stayed in his bedroom and watched television.
"He talks a lot to himself," Olgie Maynard said. "... He was never violent."
She added that Tennis Maynard "has guns, but I don't know one from another."
On Thursday afternoon, he was recovering in a hospital bed. According to the state police spokesman, Maynard is expected to survive.
He's already facing at least two serious charges: first-degree murder for Crum's death and attempted murder for firing on a sheriff's deputy.
"Those charges are pending on him getting out of the hospital," Rockel said.
Sheriff's slaying 'a big blow to the community'
The man he allegedly killed, 59-year-old Eugene Crum, had been a county magistrate and a special investigator for the prosecutor's office before becoming sheriff in January.
In 93 days on the job, Crum gained a reputation for taking a tough stance on drug dealers. His legacy will live on, Mingo County officials say.
"The flame that Sheriff Crum sparked cannot be extinguished," Mingo County Prosecuting Attorney C. Michael Sparks said in a statement read at Thursday's press conference in Williamson.
His slaying has shaken the rural county, which normally sees only one or two slayings per year, said Lt. Randy Hatfield of the Mingo County Sheriff's Office.
"It's devastating," Hatfield said. "It's a big blow to the community."
Asked whether officials thought there was any connection between Crum's slaying and the recent killing of a Colorado prison official or the slayings of two Texas prosecutors, Hatfield said, "I hope not," but declined to elaborate.
For now, the focus is on remembering Crum and his family.
In addition to Thursday night's candlelight vigil, a memorial service for Crum will be held late Saturday afternoon and his funeral will take place Sunday, both services at Mingo Central High School.
Crum will be remembered as a devoted public servant and a family man, having left behind his wife as well as several children and grandchildren.
"It's quite obvious that the last 26 hours have been a difficult time," said Hubbard, president of the Mingo County commission. "We continue to solicit your prayers."