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NORMAN, Okla. — It’s a burial mystery that went unsolved for decades.

40 hospital patients burned to death in 1918 and now archaeologists believe they have found the mass grave site.

The fire happened almost 100 years ago at the Oklahoma State Hospital, now known as the Griffin Memorial Hospital.

Communication was different back then and it took a very long time to receive and send any letters so families wanting to bury their loved ones didn’t get a chance.

On a rainy day at the Norman International Order of Odd Fellows Cemetery is where you will find red flags.

“We’re as comfortable as we can be with what we have to be able to say ‘we have nailed it’,” said Dr. Scott Hammerstedt, Oklahoma Archaeological Survey.

The red flags mark the spot where archaeologists say they have found the last resting place for 39 people who were killed and buried together after the 1918 Oklahoma State Hospital fire.

Dr Hammerstedt said, “We spent two days in January running our radar and electrical resistance equipment in a couple of areas of the cemetery trying to locate the grave.”

Griffin Memorial Hospital officials reached out to Dr. Scott Hammerstedt and his team for help to find the unmarked grave.

They didn’t have much luck at first, but someone working at the cemetery knew exactly where to look.

“The site manager came out and told us a story about his predecessor knew someone who kept saying it was in this particular area,” said Dr. Hammerstedt. “So why not, let’s go put another grid over there.”

“It just seemed like the right thing to do to find the grave site,” said Larry Gross, Executive Director of Griffin Memorial Hospital. “To memorialized these victims of this tragedy appropriately.”

Griffin Memorial Executive Director Larry Gross says the hospital is hoping to identify the victims and to get in contact with their families, but it is going to be a challenging task.

“We’re going through all the medical records of the time,” said Gross. “Medical records in those days were certainly not at the thoroughness that they are today.”

The hospital says 40 people died in that fire, 39 people were buried together, and family identified one person, therefore that person was buried separately.

The hospital is hoping to raise enough money so they can put up a monument or a grave marker to honor those victims.

Donations can be sent to Griffin Memorial Hospital, P.O. Box 151, Norman, OK, 73070.