A suspect has now been arrested and charged in connection with a body that was found at the Crissy Field parking lot two weeks ago. And surveillance footage suggests it was a calculated hit.

Federal prosecutors revealed Tuesday that they had made an arrest in connection with the murder of a man who was found shot in the head in the east parking lot of Crissy Field on November 12. The suspect is 20-year-old Leion Butler of San Francisco, and he has been charged with aiding and abetting a murder.

The crime is under federal jurisdiction, because the body was found in the federally owned Presidio. It remains unclear where the actual murder may have taken place.

Investigators found surveillance footage showing the victim's car leaving the parking lot, and it was subsequently located, double-parked and abandoned for several days in the Hunters Point neighborhood.

Per the U.S. Attorney's Office:

"The criminal complaint describes how investigators obtained additional surveillance footage from cameras near where the victim’s car was found. The additional surveillance video captured the arrival of the victim’s car and showed someone — later identified as the defendant — parking the car, exiting, and speaking into a cellphone. Further, the video captured the eventual arrival of a second car. The criminal complaint further describes how the surveillance camera captured images of the defendant speaking with the driver of the second car, the defendant making several trips between the victim’s car and the second car, and the defendant wiping down the driver’s side door and interior of the victim’s car with 'a clothing item or towel.' In addition, the video showed additional images of the defendant retrieving items from the victim’s car and eventually getting into the second vehicle and leaving the scene."

The victim has been identified by the SF Medical Examiner as Hamza Walupupu, 32, of Alameda County.

Investigators say that by identifying the owner of the second vehicle that appeared on the scene near the victim's vehicle on the surveillance footage, they were then able to identify Butler.

Butler was arrested Monday, and he remains in federal custody.

He was expected to appear before a judge in federal court on Wednesday. If convicted of murder, Butler could face a sentence of death, or life in prison.

This was San Francisco's 50th homicide of the year to date.

Photo: Michael Emono