(WJET/WFXP/YourErie.com) — State police have discovered what’s believed to be human remains during a welfare check at a Summit Township home.

What was originally a welfare check for 66-year-old Michael Maisner, after his family said they have not seen him for about three weeks, has turned into a death investigation.

According to Erie Times-News, Pennsylvania State Police discovered strange writings on the walls of Maisner’s residence and a suspected human bone in a fire pit on the property.

The chair of the applied forensic sciences department of Mercyhurst University said various aspects are taken into consideration when investigating cases similar to this one involving human bones.

“What was their position and orientation and even how long ago that occurred,” said Dennis Dirkmaat, chair of the applied forensic sciences department at Mercyhurst University. “We look at those factors and try to come up with an estimate of what we call the post-mortem interval.”

A woman named Marisa Rodriguez has been identified as living in Maisner’s home and reportedly took care of his cats but said she has not seen him in weeks.

Dirkmaat said with the help from advanced technology, extraction of DNA from human bone is still possible even if it has been burned.

“For all of these situations, there will be an attempt to determine whose bones these are. In situations out in the woods, and if they’ve been out there even 10 years, the possibility of extracting DNA is very high. The technology has advanced tremendously,” Dirkmaat added.

Rodriguez is being charged with stealing Maisner’s vehicle, according to a criminal complaint.