Federal authorities are investigating the suicide of a 76-year-old veteran who fatally shot himself in the parking lot of the Northport Veterans Affairs Medical Center on Long Island, according to Suffolk County police.

Peter Kaisen had been a patient at the hospital. He was pronounced dead Sunday outside of the nursing home at the medical center, the New York Times reported Wednesday.

The FBI has opened an investigation into Kaisen’s death because it occurred on federal property.

The Veterans Affairs medical system has remained under scrutiny for the past two years since the department confirmed in 2014 that dozens of veterans had died waiting for care at the Phoenix V.A. hospital system. Officials at the Arizona medical center deliberately omitted 1,700 patients from care wait lists and later attempted to cover up long wait times.

The Government Accountability Office published a study in April finding the VA system still had not fixed its wait-time problems.

Two officials at the Northport V.A. center told the Times that Kaisen had gone to the E.R. to seek treatment related to mental health problems and was denied service. He then "went to his car and shot himself," one unnamed employee said.

The worker said Kaisen should have been referred to the center’s mental health center, which is open at all hours. The official said that the E.R. typically doesn’t have a psychologist on hand, but that one was always on call.

"Someone dropped the ball," the employee said. "They should not have turned him away."

A spokesman for the hospital told the Times that there "was no indication that he presented to the E.R. prior to the incident."

"The employees here at Northport feel this loss deeply and extend their thoughts and prayers to all those impacted by this tragedy."

V.A. data released in July revealed that 20 veterans commit suicide each day. A large majority of those who commit suicide, 65 percent, are at least 50 years old.

More than 7,400 veterans killed themselves in 2014, the latest year of available data, accounting for 18 percent of all U.S. suicides, even though former service members make up less than 9 percent of the entire population.