ATLANTA » Loved ones today mourned two slain teenagers whose bodies were found behind a suburban Atlanta grocery store, as police prepared to move a 20-year-old suspect to an Atlanta jail.

Jeffrey A. Hazelwood was being held in Roswell’s city jail early today and expected to be transferred to the larger Fulton County Jail by Friday evening. Police weren’t saying when he was to be moved due to “safety reasons,” Roswell police Detective Zachary Frommer said.

Hazelwood was arrested Wednesday on two counts of murder in the slayings of Carter Davis and Natalie Henderson, both 17. Each teen was shot once in the head, the Fulton County Medical Examiner’s Office said.

On Friday, Frommer said Hazelwood is also charged with two counts of aggravated assault, one count of theft by taking and financial transaction card fraud. The card fraud charge stems from the use of Henderson’s credit-debit card at an area gas station after the killings, Frommer said.

Police aren’t discussing any motive, nor will they comment on the relationship, if any, between Hazelwood and the teens, Frommer said Thursday.

Detectives encountered apps used to send messages as they investigated the killings, Roswell Police Chief Rusty Grant said. He would not provide details on which apps are involved in the case, but he said gaining access to the apps and cellphones proved somewhat challenging for investigators.

Henderson appeared to be extremely active on social media. She had since September 2015 been a representative for the “Smack High” social media app, designed to connect teens with similar interests, its CEO said today.

“We are extremely saddened at Smack High to hear about the deaths of Natalie Henderson and Carter Davis,” Smack High co-founder and CEO Giuseppe Stuto said in a statement to The Associated Press.

The app’s mission “is to give teens the power to make new friends, stay connected, and communicate through the full extent of their individuality,” the app’s website states. “Our central thesis is that real-time teenage interaction actually leads to the purest form of expression and engagement, and that is our mission for all teens across the nation.”

A memorial service is planned for 10 a.m. Friday at Roswell Presbyterian Church for Henderson, H.M. Patterson & Son Funeral Directors said. She would have been a senior this year at Roswell High School.

“Our beautiful shining girl: Natalie, a rising senior at Roswell High School, was smart, funny, sassy, and strong, a free spirit with a gorgeous smile that could make your day or your week,” her obituary from the funeral home said.

“Natalie had a loving heart and an infectious zest for life. Unusual for one so young, she had the courage to always be, unapologetically, herself.”

On Thursday, a celebration of life service was held for Davis. The Rev. James Hamner read a statement to reporters from Carter’s parents, Michele and Jeremy Davis.

“Whether he was dribbling a soccer ball, throwing a football, or making a fast break in lacrosse, Carter’s athleticism and passion for team sports was evident,” Hamner said.

“Although his life was cut short, everyone in his life will remember how he loved the Lord, loved everyone, and told them often. He lived life to the fullest.”

Davis lived in Rapid City, South Dakota, during part of his high school years. He was about to start his senior year at River Ridge High School in Woodstock, Georgia.

In recent months, Hazelwood had been staying with various friends and relatives in Roswell and in nearby Cobb and Cherokee counties, Frommer told the AP.

Hazelwood was mostly raised by his grandparents in the Roswell area, his aunt, Kathy Dinwiddee, told WAGA-TV.

“He has some hurt and anger in him, but I don’t know what it was about, only Jeff could tell you,” Dinwiddee told the Atlanta station.