NBC -- A Portland man was found dead in a sinkhole in his backyard Sunday morning.
When police and firefighters arrived at the scene early Sunday, they found the lights on, the front door locked, and a car in the driveway, but no sign of the resident.
It wasn't until they began to pump water from a backyard hole that they found Michael Zerwas, 57, dead in the sinkhole.
The hole was found in the middle of Zerwas' garden, about five feet wide and 25 to 35 feet deep. It appeared to be a cistern dating back to the 1930's construction of the home.
An autopsy performed on Zerwas' body indicates he survived the fall into the sinkhole but was unable to pull himself to safety. In water reported at 45-to-50 degrees, the medical examiner says he likely became hypothermic and drowned.
With no immediate family to notice his absence, Zerwas wasn't reported missing until the weekend, when a friend from Iowa called police and asked that they check his home.