The family of Bijan Ghaisar, far right in white shirt, visits the National Christmas Tree on Christmas Eve 2016. They spent Christmas Eve 2017 outside a U.S. Park Police station in McLean, Va., asking why he was killed. (Ghaisar family photo)

Bijan Ghaisar’s family had a tradition of driving into Washington from their home in McLean, Va., every Christmas Eve to see the National Christmas Tree near the White House. This Christmas Eve, his family stood outside of a U.S. Park Police station on the George Washington Memorial Parkway and pleaded for information on why Ghaisar was shot and killed by Park Police officers more than a month ago.

“We want everybody here that has stayed silent, protecting our son’s shooter, to know that staying silent is the equivalent of pulling the trigger,” said his mother, Kelly Ghaisar. “We are demanding that someone start talking about the killing of our son.”

Ghaisar, 25, was shot by one or two Park Police officers as he sat inside his Jeep Grand Cherokee in the Fort Hunt area of Fairfax County, Va., on Nov. 17. His family said he was unarmed. The Park Police said Ghaisar’s Jeep had been involved in a traffic accident on the George Washington Memorial Parkway in Alexandria and that Ghaisar left the scene. Park Police officers then pursued him down the parkway, with a Fairfax County officer behind them. When Ghaisar stopped at the intersection of Fort Hunt Road and Alexandria Avenue, two officers walked toward his Jeep and began firing, a witness told The Washington Post.

Three days after the shooting, the Park Police handed the investigation off to the FBI. The Justice Department’s civil rights division and the U.S. attorney’s office in Washington is overseeing the investigation.

Neither the Park Police nor the FBI has explained why Ghaisar was shot, who the officers were, or the circumstances surrounding the initial accident and pursuit. The shooting was captured by the Fairfax officer’s in-car camera, but that video has not been released. The Park Police do not have in-car or body-worn cameras.

Ghaisar’s family said Ghaisar, an accountant who grew up in McLean and lived in Tysons Corner, was shot three times in the head. He lived for 10 days, and was pronounced dead on Nov. 27.

A Park Police spokesman did not reply to a request for comment Sunday.

From left, Kouros Emami, the brother-in-law of Bijan Ghaisar, James and Kelly Ghaisar, his parents and Negeen Ghaisar, his sister, stand in front of the U.S. Park Police George Washington Memorial Parkway Station on Sunday seeking answers in Bijan Ghaisar’s shooting death by Park Police last month. (Toni L. Sandys/The Washington Post)

The Ghaisar family stood outside the Park Police’s Parkway Station, near Turkey Run Park in McLean, holding signs which read, “It has been 37 days since you shot our Bijan,” “All we want for Christmas” “Is who shot him and why? #WeAreBijan.”

Ghaisar’s mother, father James, sister Negeen and brother-in-law Kouros Emami stood silently for several minutes, then attempted to go inside the station. No one would open the door, though staff working inside earlier had allowed a reporter inside to use the bathroom. Kelly Ghaisar pressed the intercom button and was told someone would come out, but no one did. She called the phone number for the Park Police and was told someone would speak with them, but no one did.

After the Ghaisars left, a Park Police officer drove up and said he was given instructions to refer the family to the FBI.

“We have no answers,” Kelly Ghaisar said. “We don’t know why. We don’t know if they read him his rights. We have no idea what they did to him. He was a peaceful, loving son. There’s got to be justice for Bijan, and we will not stop.”

Christmas was Bijan Ghaisar’s favorite holiday, his family said, including the annual trip to the national tree. “Today, we’re here instead,” his sister Negeen said. “Bijan was our Santa,” his mother said. “He delivered all of our Christmas gifts, in the Jeep he was shot in, to all of our family and friends.”