Maine State Police are investigating the suspicious death of a man whose body was discovered Wednesday afternoon inside a home at 45 Campground Road in Arundel.

The body of 63-year-old Matthew Coito was found by a relative in the kitchen of the two-story home on a wooded lot off Campground Road, State Police spokesman Stephen McCausland said in a news release.

Coito’s wife, 65-year-old Sue Kim Coito, remained unaccounted for as of Wednesday evening, McCausland said. Maine state troopers and deputies from the York County Sheriff’s Office are searching a wooded area behind their home for Sue Coito, who has Alzheimer’s disease. She is 5 feet, 2 inches tall, 130 pounds, with black hair and brown eyes.

“If she is not located tonight, an expanded search will take place (Thursday),” McCausland said. Family members became concerned and went to check on the couple after not hearing from either of them since last weekend.

Family members found Matthew Coito’s body around 3 p.m. Wednesday and called 911. The York County Sheriff’s Office was the first law enforcement agency to respond.

Police hope that an autopsy scheduled for Thursday at the state Medical Examiner’s Office will reveal how Coito died.

Sgt. Chris Harriman said at a news conference outside the home late Wednesday afternoon that investigators are not treating Coito’s death as a homicide.

“We’re investigating it as a suspicious death at this point,” he said.

When asked if there was a threat to the public, Harriman replied, “I don’t think so. But like I say, it’s the beginning stage of the investigation and we’re really not sure what happened yet.”

The Maine State Police Major Crimes Unit responded to the scene. Troopers used a police dog to search for evidence at the rear of the property.