ROSWELL, Ga. - Police arrested a 20-year-old man on a murder charge Wednesday as they investigate the deaths of two teenagers, each shot in the head, whose bodies were found behind a grocery store in an Atlanta suburb.

Roswell police chief Rusty Grant said Jeffrey A. Hazelwood was arrested in the deaths of Natalie Henderson and Carter Davis on Aug. 1. While investigators are unsure of the motive, they believe Hazelwood acted alone, the chief said.

Hazelwood was being held at the Roswell Detention Center pending transfer to the Fulton County Jail.

A delivery driver spotted the bodies behind a Publix store, Det. Zachary Frommer said. The Fulton County medical examiner said each teen was killed by a bullet to the head.

The two 17-year-olds were about to start their senior years at high school. Henderson attended Roswell High, just across the street from the Publix, and Davis was a standout lacrosse player at River Ridge in nearby Cherokee County.

Davis also played lacrosse in Rapid City, South Dakota, before returning to finish high school in Georgia, where he had lived as a child, Black Hills Lacrosse Association past president Richard Sudmeier said.

"Our players up here in Rapid City, we called him 'Georgia.' That was his nickname," Sudmeier said in a telephone interview with The Associated Press on Wednesday.

Davis wore No. 6 when he played on the Black Hills Lacrosse team, so Sudmeier said teammates may wear helmet stickers with the number in his honor.

The South Dakota players plan to gather Friday to remember Davis, who was always willing to help his former teammates improve and "was pretty much like a second coach," said Zach Hockert, the varsity coach at Black Hills Lacrosse.

"If I could have a whole team of Carter Davises, we'd be unbeatable," Hockert said Wednesday.