LITTLE ROCK, Ark. (AP) — The 14-year-old grandson of an Arkansas couple found dead behind their home was arrested Thursday and was awaiting arraignment on two counts of capital murder.

Prosecutor Cody Hiland said late Thursday that more arrests were likely in the slayings of Robert Cogdell and his wife, Patricia, who were found fatally shot Wednesday afternoon in a wooded area behind their Conway home about 35 miles north of Little Rock.

Conway police spokeswoman LaTresha Woodruff said the Cogdells were raising the grandson and he lived with them. She said he became a suspect after investigators talked with family and friends.

Hiland said the grandson will have his first appearance in court Friday morning to determine bond, but no formal charges will be brought against him until prosecutors review the full investigative file including evidence reviewed by the Arkansas State Crime Lab.

“I anticipate that there will be additional suspects arrested in this case,” he said.

Hiland said he hadn’t yet determined whether the boy would be charged as a juvenile or an adult.

Woodruff said the investigation was ongoing when asked whether police had determined a motive in the slayings.

“We are still trying to figure out exactly what happened, and that is not something that we would speculate at this point,” she said.

Police were asked to check on the couple after Robert Cogdell’s co-workers became worried that he hadn’t come to work Wednesday. Cogdell was the public works director for the city of Maumelle, just northwest of Little Rock.

The teen was taken into custody at a house a few miles from the Cogdell’s residence an hour or two after the bodies were discovered, Woodruff said.

Woodruff said the boy was being held at the Faulkner County Jail at least until his bond hearing.

Because he is a minor, the teen’s information was not listed on the jail’s website and it was unclear whether he had an attorney who could comment on the allegations. Hiland said he had not received any attorney information for the boy.

The Cogdells, both 66, lived with the boy on a sparsely developed road behind a large housing development, lined with trees and fields.

Woodruff said investigators believe the couple were shot Tuesday night. She said based on evidence at the home, Robert was likely killed inside the house and Patricia was likely killed in the garage. She declined to release any more details about the couple’s injuries.

Woodruff said investigators believe the bodies were dragged to a line of trees behind the home, where they were found Wednesday.

Woodruff said because the investigation is still open, it’s possible other arrests could be made and other charges could be filed.

Meanwhile, Maumelle Mayor Mike Watkins said city officials and employees were “in shock.” He said Cogdell was the city’s first and only public works director, having taken the job in 1985 when the city was incorporated.

“Robert will be greatly missed,” Watkins said Wednesday night.