As the three-year anniversary approaches of the fatal shooting of Bijan Ghaisar by two U.S. Park Police officers, Sens. Charles E. Grassley (R-Iowa) and Mark R. Warner (D-Va.) revealed this week they have received briefings from the National Park Service, the Fairfax County police chief and two from the Justice Department. But the senators said they still have not been told why the officers fired 10 shots into Ghaisar’s Jeep Cherokee while he was slowly driving away from them.

Meanwhile, the Fairfax prosecutor handling the criminal investigation has added the Fairfax police to the case, once the Justice Department said the FBI would not cooperate after doing its own two-year probe.

Ghaisar, 25, a Northern Virginia native and accountant with no criminal record, was shot as he maneuvered his jeep away from Officers Alejandro Amaya and Lucas Vinyard on Nov. 17, 2017. Ghaisar was unarmed and did not appear to interact with the officers as he twice stopped and then pulled away as they ran at him with guns drawn, nor was there an exchange when Ghaisar started to drive off a third time in the Fort Hunt neighborhood of Fairfax County.

Ghaisar died 10 days later of multiple head wounds. The pursuit of Ghaisar, the two stops before the shooting, and the gunfire itself was captured by the in-car camera of a Fairfax police lieutenant who followed the Park Police officers down George Washington Memorial Parkway into the neighborhood. Amaya and Vinyard were trying to stop Ghaisar because he had been involved in a fender bender in Alexandria minutes earlier and left without speaking to the other driver.

The shooting was investigated by the FBI, and a decision not to charge Amaya and Vinyard, by the Justice Department’s Civil Rights Division and then-Washington U.S. Attorney Jessie K. Liu, was made last November. The ruling did not preclude local authorities from pursuing the case, and newly elected Fairfax prosecutor Steve Descano said he would investigate when he took office in January.

In February, the Justice Department told Descano it would not allow the FBI to cooperate with his investigation, because it conflicted with their interests in a civil suit filed by the Ghaisars. Descano in June asked Justice to clarify its stance, since it did not enter the suit against the officers, and to release 260 withheld documents. “The DOJ’s response to our requests has not been substantive,” Descano spokesman Antonio Peronace said Tuesday, so Descano recently asked the Fairfax police to join the case. The police agreed, Peronace said.

Grassley and Warner began seeking answers from the Justice Department and the Park Police, a branch of the National Park Service, since late 2018. “As a result of our nearly 18 months of inquiries,” the senators wrote in a letter Monday to David Vela, the acting head of the park service, “the DOJ/FBI, Fairfax County Police Department, and more recently, NPS, finally provided briefings to us and our staffs.” Warner also has been withholding approval for appointees in the Interior Department, the parent agency of the Park Service and the Park Police, and in May placed a hold on one nominee.

But, the senators said, “we are very disappointed at the lack of information that was provided” by the park service. “Your staff refused to answer any substantive questions based on tenuous and incoherent legal arguments ... on the grounds that this investigation is ‘ongoing,’ despite the fact that the FBI and DOJ have closed the case." The park service pointed to Descano’s investigation in Fairfax, but the senators said the park service “could cite no policy for their refusal to provide answers.” Grassley and Warner said they have received briefings from other federal law enforcement agencies during investigations, including one just days after the 2018 mass shooting at a high school in Parkland, Fla., and also after shootings last year in El Paso and Dayton, Ohio.

The senators sent a long list of unanswered questions about the case, such as whether Vinyard and Amaya were following Park Police protocol by approaching Ghaisar’s Jeep Grand Cherokee with guns drawn, whether they had radio communication with other Park Police personnel, and whether Ghaisar threatened the officers. They asked “which of Mr. Ghaisar’s actions, if any, prompted the officers to believe utilizing deadly force was necessary?” The senators also note that the Park Police officers did not provide any first aid to Ghaisar after shooting him, and asked if that is the department’s policy.

Based on the Fairfax police video of the shooting, the letter raises a new point: That the officer on the passenger side, Amaya, who fired the first shots at Ghaisar, can then be seen climbing back in the Park Police vehicle and closing the door while Vinyard, the driver, continued to fire. The Justice Department said in November it was Vinyard’s shots that killed Ghaisar, and that 10 shots had been fired, though only nine can be heard on the video.

“Why did this officer [Amaya] essentially disengage and feel the need to get back in the vehicle?” Grassley and Warner asked. “Did this officer believe the threat had been diminished? Why did the second officer [Vinyard] feel the need to continue to engage with Mr. Ghaisar?”

Vinyard and Amaya have been on paid administrative duty since April 2019 and have not spoken publicly about the case. The Park Police have said they will not begin an internal affairs review of the case until decisions are made on any criminal charges. A spokeswoman for the National Park Service and a spokesman for the Park Police both declined to comment on the senators’ letter Tuesday.

Fairfax County Police Chief Edwin C. Roessler Jr. also declined to comment Tuesday about what he told the senators’ staffs. When the shooting happened, Fairfax police responded to the scene, but Roessler said they were told by Park Police that no Fairfax help was needed. Park Police have legal jurisdiction in Virginia, though they soon handed the case to the FBI. Roessler’s internal affairs then investigated the actions of the Fairfax officers, to include the lieutenant who followed the pursuit, a second officer who arrived on the scene just as the shooting started and can be glimpsed in the video, and another officer who also arrived and helped pull Ghaisar out of the jeep and called for help, according to police reports.

In early 2018, Roessler released the lieutenant’s in-car video of the incident, over the objections of federal authorities. He has also released Fairfax police reports and the second officer’s in-car video of the shooting.

In August 2018, Ghaisar’s parents and sister sued the Park Police and the officers. The suit has been split into two cases, and court records indicate that pretrial discovery is continuing and pretrial conferences are set for later this month. But no trial date has been set. The lawyers for the Ghaisars declined to comment Tuesday.