Authorities in Maryland say a man who told police his terminally ill father killed himself is charged with first-degree murder.

Cpl. Amanda Ensor of the Frederick County sheriff's office said Friday that 18-year-old Garrett Barker is charged with killing his 47-year-old father Kevin.

The 18-year-old is being held without bail. No defense attorney is listed in court records.

Ensor says Barker told deputies July 11 that his father had shot himself.

The Frederick News-Post reports investigators found a handgun and shell casing on Kevin Barker's chest and initially concluded he took his own life. Charging documents say other relatives later became suspicious and called deputies back.

Investigators say they listened in on a phone call in which Barker said his father "grabbed my hand and made me pull the trigger."