ALEXANDRIA, La. -- Hospital officials called it an accident when a 70-year-old psychiatric patient was fatally injured in an altercation with a nursing assistant at a Department of Veterans Affairs medical center in central Louisiana three years ago.

But the case became fodder for the VA's congressional critics after local prosecutors charged the employee, 54-year-old Fredrick Kevin Harris, with manslaughter in the death of Air Force veteran Charles Lee Johnson.

Johnson died a year before a national scandal erupted over chronic delays for veterans seeking medical care. The deadly encounter has drawn the Alexandria VA Health Care System into a broader conflict between the VA and its Republican opponents, who complain the agency has fired few workers for poor performance.

The House Committee on Veterans' Affairs has pressed VA officials to explain why they haven't fired Harris, who has remained on its payroll while awaiting trial.

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Committee chairman Jeff Miller, a Florida Republican, cited the case against Harris during a Dec. 9 hearing and said he sees "no real acceptance of responsibility for VA's continued and pervasive failure to seriously discipline its employees."

Harris was placed on paid leave after his arrest but returned to work in December in a "non-patient care area," according to the VA. His Monday trial date is expected to be postponed.

VA spokesman Randal Noller declined to explain why Harris has been allowed to resume working. The agency has said federal civil service rules make it difficult to fire poor-performing employees and has recommended changes to Congress.

VA officials cleared Harris to return to work and care for patients within days of the March 13, 2013, altercation at the Pineville medical center. Johnson died at a nursing home on May 1, 2013.

The episode could have ended there. Instead, a skeptical coroner laid the groundwork for a criminal investigation that led to Harris' arrest in December 2013.

In this undated photo, Donald Burke, of Pollock, La., holds an old photograph of his brother-in-law, Charles Lee Johnson, who died in May 2013 following an altercation with a nursing assistant at a Department of Veterans Affairs medical center in nearby Pineville. Michael Kunzelman, AP

Grant Parish Coroner Dean Nugent arranged for an autopsy that found Johnson died from blunt force trauma to the head. Even before the autopsy, Johnson's relatives doubted his injuries came from an accidental fall.

"They tried to cover it all up," said brother-in-law Donald Burke, 80, of Pollock.

George Higgins III, Harris' attorney, said his client didn't mean to hurt Johnson and received annual training on proper techniques for restraining patients.

"There was absolutely no intent, in any manner, shape or form, to harm this patient," Higgins said. "The only thing he was doing was trying to protect other patients and staff members."

Johnson's sister, Elizabeth Burke, filed a wrongful death claim against the VA in 2014, seeking $1 million. The VA agreed last March to pay $215,000 to resolve her claim.

"It hurt me very much. He was my little brother," Burke said.

Johnson's death certificate says his medical conditions included schizophrenia and dementia. Donald Burke said Johnson frequently sought treatment for panic attacks, including one that sent him to the hospital before the altercation.

"I've never known him to get into a fight of any kind," Burke said. "He was just a common, ordinary old man."

The Burkes said somebody from the VA medical center initially called to tell them Johnson had been injured in a fall and was transferred to another hospital in Alexandria.

Donald Burke said Johnson was drifting in and out of consciousness and couldn't remember what had happened. Gregory Jones, an attorney for the family, said Elizabeth Burke noticed bruises and marks on the side and back of Johnson's neck.

"It jumped out at her as not consistent with a fall," Jones said.

Burke said the coroner contacted him hours after Johnson's death. He said Nugent concluded that bruises on Johnson's neck couldn't have come from a fall. A coroner's report isn't publicly available, and Nugent declined to be interviewed. The death certificate lists blunt force trauma to the head as the underlying cause of death but lists the manner of death as "pending investigation."

The VA's Office of Inspector General opened a criminal investigation after Johnson died. One of its investigators, Thomas Bennett, outlined his findings during a court hearing a week after Harris' arrest.

Bennett said witnesses told him Harris had "slammed the patient's head into the wall" in the hospital's acute mental health unit.

"Do you mean physically slammed his head or threw him where his head was slammed into something?" asked Higgins, Harris' attorney.

Bennett said witnesses gave "different variations."

"Not physically grabbing his head and slamming it into a wall, but Mr. Harris had the patient entangled by his arms," Bennett testified. "During that altercation, he slammed the patient's head with force into the wall this way. Not grabbing his head, but by grabbing his body."

The VA's Office of Congressional and Legislative Affairs provided Rep. Miller's committee with a different account of the altercation in December 2015. The VA office said Johnson became "combative and agitated," charged at Harris and fell after the nursing assistant tried to "redirect" him during the struggle.

In 2008, Harris was arrested on an assault charge after he allegedly punched a relative in the face during an argument at his Alexandria home, according to a police report. But his arrest didn't lead to a conviction. It's unclear whether Harris' VA supervisors knew about his arrest or could have disciplined him for it.

Donald Burke said a prison sentence wouldn't bring his family any comfort, but he hopes Harris never cares for another patient.

"We don't want to see anybody else injured like this," he added.