FRONTENAC, Mo. – Detectives searched and dug in a yard in Frontenac, looking for clues in a 1972 missing person case.

The property was on Country Estates Place in Frontenac, with the area being searched just off Geyer Road.

Frontenac police, along with the FBI and the St. Louis County Medical Examiner’s Office, focused on one particular corner of the backyard, putting up police tape along the edge of where they searched, right next to Geyer Road.

“We’re doing a follow-up investigation related to a missing person case from 1972,” Frontenac Police Lt. Tim Duda said.

Duda couldn’t say much about what they’re looking for, as we watched them using large sifters.

“We have some new evidence that’s been corroborated, which has led us to the investigation that we’re conducting today,” Duda said.

This dig comes about two weeks after a cadaver dog search at the same location. Police say Marie Beulah Mueller used to live here with her husband, Dr. Donn Mueller. It wasn’t until March of 1972 that Donn reported Marie missing.

Police say Donn then moved out and has since died. Duda said there is no threat to the public.

“All of a sudden, I saw the police presence and wondered, and then I saw you and wondered what was going on,” said neighbor Cindy Heffernan. “When I saw the family, the current family wants to know what happened to their loved one from 50 years ago. Hopefully, they get some closure.”

After several hours, investigators determined there was nothing to test, for now.

“Whatever we come up with will go to a lab,” Duda said.

Their investigation, however, will continue. Investigators hope anyone with possible information about the 1972 disappearance to call Frontenac Police at 314-994-9300.