The video shows the confrontation escalating into a physical assault and ending with gunshots, Schirmer told the Courier Times.
Autopsy results released Tuesday indicate Steven A. Panebianco, 30, of Bensalem, sustained gunshot wounds to the right thigh and torso, and Raymond A. Farrell IV, 28, of Philadelphia, sustained "multiple" gunshot wounds, the paper said.
At least five to six bullets were fired, the Courier Times reported, adding that police said Panebianco and Farrell each were shot more than once.
The Bucks County district attorney confirmed the shooter has a valid permit to carry a firearm, the paper said, adding that a firearm was recovered at the scene.
The Bucks County coroner's office listed the manner of death as homicide, noting those deaths are classified as at the hands of another person, the Courier Times said, adding that no decision on criminal charges is expected until later this week.
Authorities have not identified nor have they interviewed the 24-year-old man who was shot and wounded in the incident, but Schirmer told the paper he's no longer hospitalized.
The alleged shooter is 21 years old, but his name hasn't been released, the Courier Times said. He called 911 and identified himself as the shooter and remained on the scene until police arrived, the paper said, adding that police said he's been cooperating with investigators.
Schirmer declined to say if the alleged shooter was hurt, the Courier Times noted.
Friends and family of Panebianco and Farrell told WPVI-TV they want answers about what happened.
"I'm going to miss watching them grow, watching them grow to the men that they are because it's been non-stop," Michael Maranon told the station, adding that the pair were among his best friends.
Justin Jordan, Farrell's brother, told WPVI that Farrell has a young son and Panebianco was celebrating getting a new job: "Ray was a terrific father, family man, an honest worker. Steve — the same thing. We were actually going to stay in last night and go to his son's soccer game this morning. That was the plan."