A man with psychiatric issues awaiting sentencing for federal charges of armed bank robbery and carjacking killed himself in the Alexandria jail, authorities said Wednesday.

Christopher Lapp, 62, was found unresponsive and alone in his cell at 1:37 a.m. on May 18, after a suicide attempt, according to the sheriff’s office. Deputies, medical staff and medics were not able to revive him; he died at 6:32 p.m.

Lapp had been deemed incompetent for trial due to mental illness in early 2020, according to court filings. For the next year, he received psychotropic medication at Butner federal prison in North Carolina, which handles inmates with mental health issues. In February, Lapp was deemed competent to stand trial.

But, according to court filings from the defense attorney, Lapp was then brought to the Alexandria jail, where his medication was discontinued “after a staff clinician opined Lapp was not mentally ill.”

Sheriff Dana Lawhorne said “that is not an accurate depiction of the care [Lapp] had received while in the custody of the Alexandria Detention Center.” He didn’t give details, citing privacy laws.

Clinicians at the jail come from the city’s Department of Community and Human Services, a spokeswoman at that agency said, adding that “an internal and external review of this case will take place.”

According to court records, on Nov. 13, 2018, Lapp entered a Wells Fargo bank in Great Falls, Va., wearing a beige mask, sunglasses, jacket, gloves and baseball cap. He picked up a plastic bag from a trash can, pointed a gun at a teller and demanded cash. He followed a customer out of the bank, getting her car keys at gunpoint. Lapp parked at his home nearby and took the bag of money inside, according to a statement of fact; he confessed soon after being confronted by police. He pleaded guilty in April and was set to be sentenced in October. During the plea hearing, Lapp’s attorney Joseph Flood said in a filing, he “advised the Court that while he believed Lapp was competent to enter a guilty plea, he was nonetheless concerned the Detention Center had discontinued Lapp’s medication.”

The court ordered Lapp returned to Butner for further treatment, but Flood said in a subsequent filing that the prison could take him only if he were found incompetent or ordered to undergo a new psychiatric evaluation.

Lapp had a doctorate in nuclear engineering from the Massachusetts Institute of Technology. His father, R.E. Lapp, worked on the Manhattan Project before speaking out about the dangers of atomic weapons.

“He went his own way in that field and worked on different things than his father had worked on,” said Michael Golay, a professor at MIT who co-authored a 1997 paper with the younger Lapp on nuclear power plant construction. “I enjoyed him a lot.”

Members of Lapp’s family declined to comment. A spokesman for the Alexandria Sheriff’s Office referred questions to the Alexandria police, who will investigate the death. The police department had no immediate comment.

After Lapp’s death, Judge T.S. Ellis III dismissed the indictment against him.

This article has been updated to include comment from a spokeswoman for the Department of Community and Human Services.