State authorities on Tuesday charged the brother of one of the eight relatives slain in an unsolved massacre with tampering with evidence and vandalism over the destruction of a GPS tracking device they placed on his truck.

The state attorney general's office accused James Manley of destroying the device being used in the investigation of the slayings.

The charges "are not uncommon when a witness destroys such a device used in a government investigation," the attorney general's office said.

Manley, of Peebles, is the brother of victim Dana Rhoden. His phone is disconnected, and online court records don't list an attorney for him. His father, Leonard Manley, told the Cincinnati Enquirer his son would turn himself in.

Seven adults and one teenage boy from the Rhoden family were slain in April 2016. They were found shot at four homes near Piketon, 70 miles (113 kilometers) south of Columbus. Three children were found unharmed.

Investigators put a tracking device on a truck driven by James Manley, according to a search warrant obtained by the newspaper from Leonard Manley.

The search warrant indicated that investigators believe the truck was used in connection with an aggravated murder or by a person intending such a crime, but it doesn't specify a connection to the Rhoden homicide investigation and doesn't name James Manley as a suspect, the newspaper reported.

An agent with the state Bureau of Criminal Investigation placed the device on James Manley's truck on April 22, according to his arrest warrant, timestamped Tuesday. The device stopped functioning on April 28, the warrant said.

Agents went to Manley's residence in rural Pike County on May 15 to provide notice of the device. As they approached, Leonard Manley swore at the agents and said his son had found and destroyed the device and "that things not on the truck," the warrant said.

Leonard Manley, who lost three grandchildren in the massacre, told the newspaper that his son and his eldest daughter were close and there is no way he could be involved in the killings. He said it seems investigators are "grasping at straws."

"It's like a wound and then you pick at it," he told the Enquirer, "and they are starting to pick pretty hard."

Investigators also have taken a trailer linked to the family of one victim's ex-boyfriend.

The trailer was taken from one of multiple sites that authorities searched late last week. Bernie Brown, who owns property in Peebles where the trailer had been stored, said its owners needed a place to keep household items after recently selling their Adams County farm.

Whatever significance the trailer might have hasn't been publicly disclosed. The Pike County sheriff and the state attorney general's office won't discuss details of any searches or other parts of the investigation into the slayings.

No arrests have been made, and family members have pleaded for anyone with information that might help solve the case to come forward.

Authorities have executed several dozen search warrants in the investigation.