Investigators searching a farm for a missing man found two groups of decomposing human remains, possibly belonging to two people, and arrested a couple who live on the property, authorities said Monday.

Police were looking for Caesar Ruvalcava Ortiz after receiving a tip that someone was killed on the farm in August 1997, Johnston County Sheriff Steve Bizzell said.

During the weekend, deputies found plastic bags of decomposing body parts buried under the floorboards of the farm house, and a second cache of remains buried underneath a shed in a freezer, Bizzell said Monday.

He said investigators suspect that at least some of the remains are those of Ruvalcava.

Robert Bruce Pollard, 34, was charged Saturday with first-degree murder and his wife, Cecilia Louise Pollard, 34, was charged with being an accessory to murder.

Bizzell said Ruvalcava and his girlfriend, Robin Clark — a relative of Louise Pollard — often stayed with the Pollards in 1997.

Relatives reported Clark missing in August 1997, when she was 17, said Ronnie Stewart, chief of operations for the Wake County Sheriff's Department.

Bizzell said deputies were trying to locate Ruvalcava's relatives in Texas and Mexico.

Bobby Pollard, also charged with possessing a sawed-off shotgun, was ordered held without bail; Cecelia Pollard's bail was set at $500,000.