The remains of two people were found in the backyard of a missing mother and father's home, while their adult son has fled the country and is considered a suspect in the investigation, Arizona police said.

Officers were called to a home in Litchfield Park to conduct a welfare check for three people—a husband, wife and their son Matthew Flores, 27—on Tuesday, the Avondale Police Department said.

Officers found the house empty during the welfare check, but found evidence suggesting foul play, Avondale officer Daniel Benavidez said at a news conference on Thursday. Benavidez said Flores is now considered a suspect in what remains a missing persons investigation.

Benavidez said Flores fled the country, but declined to provide any further details about him or his whereabouts. "I can't give you specifics on where to look in the world. All I can say is he fled the country," he said.

The remains that were found in the backyard have yet to be identified, he said.

Asked about the evidence of foul play at the home, he said: ”What I can say that we identified is a large amount of blood, and we also identified what we believed is evidence in an attempt to conceal that blood.”

This is a developing story. More to follow.