Mystery Deepens: Son Flees as Human Remains Found in Family's Yard

Police believe the son, Matthew Flores, 27, fled before officers' welfare check.

A homicide investigation is underway after human remains were discovered in the backyard of an Arizona home, and the alleged suspect is believed to have fled the country, authorities announced Thursday.

The case began when relatives requested a welfare check for three residents -- a husband, wife and their adult son -- at their home in Litchfield Park, a community about 20 miles outside of Phoenix, the Avondale Police Department said.