(CNN) -- New police dashcam video shows the aftermath of a deadly plane crash on an Atlanta-area highway earlier this month.
Greg Byrd, 53, and his two sons, Christopher, 27, and Phillip, 25, died in the crash on May 8, along with Christopher's fiancee, Jackie Kulzer. The four were headed to the University of Mississippi in Oxford to see Greg Byrd's younger son, Robert, graduate.
It appears to bank right then disappears behind a tree line. A black cloud of an apparent explosion rises up. At first the tape is silent, but then sound pops in. The police car, siren blaring and engine roaring, zooms through intersections to reach the crash site.
The single-engine Piper PA-32 had just left DeKalb Peachtree Airport. Shortly after 10 a.m., the plane collided with an Interstate highway barrier during a forced-landing attempt, according to a National Transportation Safety Board preliminary report released this week.
'We're going down'
According to the NTSB, the pilot -- in cross talk with the airport control tower -- said, "I'm having some problem climbing here." Then he said, "Were going down here at the intersection." That was the last transmission made by the pilot.
On the police tape, the officer breathes heavily as his patrol car closes in on the ever-growing plumes. "Send everything," he radios in. Then he drives up a highway off-ramp shoulder in the opposite direction of traffic.
The police car cuts through a grassy median and comes to a halt. The crash site and flames are seen in the middle of the dashcam video. A person is outside her vehicle, with the door open.
A warning to onlookers
The officer yells "get back, get back, get back, everyone get the hell away from it." The woman runs away, her car pulls off with its door open. A man walks by and the officer asks him, "Which way is this? Is it eastbound or westbound? The officer radios in the information he gives him.
"There's someone screaming in there"
Someone says, "I thought it was gonna hit me." Then a man walks up with a small fire extinguisher. A voice tells him, "I don't think that's gonna do much." The man answers, "Yeah, but there's someone screaming in there."
The cause of the crash is still under investigation. The NTSB's final report should be released in a few months.