STONE COUNTY, Ark. – Authorities in Stone County said Thursday they have made an arrest in the investigation into four killings in April and that the suspect was related to two of the victims.

Officials with the Stone County Sheriff’s Office said 54-year-old Donnie Lee Trammell is facing four counts of first-degree murder along with multiple other charges. He has been in custody since April 22, the day after the killings.

Investigators with the SCSO and the Arkansas State Police said a family member found 77-year-old Shirley Watters and her 55-year-old son James Watters dead in their home on April 21.

Just eight hours later, 75-year-old William Clinton Trammell and his wife 72-year-old Sharon, Donnie Lee Trammell’s parents, were found killed in their home.

Special agents with the ASP noted that the killings were just a quarter-mile apart and that all of the victims had died from gunshot wounds. Deputies were warning residents to lock their doors as a search for possible suspects continued.

Trammell was initially arrested on unrelated probation violation charges. In addition to the murder charges, he now faces two counts each of aggravated burglary and possession of a handgun by a felon, theft of a firearm and possession of illicit moonshine.

He is being held in Stone County Jail on a $4 million bond. Officials with the sheriff’s office described Trammell as a “habitual offender.”

The deputies noted that the investigation into the case is ongoing but that there is no public threat. Investigators did not give a motive or reason for the killings and said they were limiting the release of details as the investigation continues.

Neighbors said at the time that they were shocked at the deaths in the normally quiet area.

“The word went out to keep your doors locked and know who’s coming up your driveway,” neighbor Roger Dunham said. “It’s just amazing that that happened here, it’s unbelievable.”