DEKALB COUNTY, Ga. -- Investigators are trying to figure out how a man, accused of pulling a gun on a driver who gave him a ride, wound up dead in a DeKalb County lake.

On July 5, police said John Hale, 61, picked up Joshua Allen, 29, at a Citgo gas station in Henry County and the pair drove away toward DeKalb County. As they approached the intersection of Ward Lake Road and Bouldercrest, police said Allen pulled out a silver and black semi-automatic handgun and pointed it at Hale.

That's when Hale allegedly told Allen that he "didn't have to do this," to which Allen said "Yeah, I think I do." In the next moment, Hale said the two began to struggle over the gun while the car was still moving.

At some point, the gun went off inside the car, hitting Hale in the top of his head. The car then flipped into an embankment on Ward Lake Road, drawing the attention of several witnesses. Police said Allen and Hale got out of the car and continued to struggle over the gun, while one of the witnesses pleaded for Allen to spare Hale's life.

Allen then tossed the gun under the overturned car, said "I'm just doing this for my family," then ran away from the crash toward the woodline of Panthersville Road.

When officers got to the scene, they treated Hale for a laceration on his leg and transported him to the hospital.

Officers processed the crash site where they found another person's ID and a money order for $3,500. They also found the handgun and and a shell casing.

Police had been trying to find Allen, who was reported missing from Clayton County, since the incident. A week later, they recovered his body from the lake about a mile away. 11Alive's SkyTracker flew over the scene on July 12 while police worked the scene.

At this time, officials don't have an exact cause of death for Allen or how he wound up in the lake.

PHOTOS | Body recovered in DeKalb County lake

Erica Solomon contributed to this story.