By Chris Wright, The News On 6

BARTLESVILLE, OK -- Investigators now believe the fire that destroyed an historic Bartlesville building was caused by a meth lab.  Much of the May Brothers Building burned down on August 31st.  It was a Bartlesville landmark for nearly a century.

Evidence of a meth lab was found in a vacant area on the second floor of the building.  Investigators say this revelation makes this fire even more tragic.

It took only a few hours to destroy 99 years of Bartlesville history.  The May Brothers Building, which housed a family-owned department store, had stood in Bartlesville since 1910.

"Seeing something like this leaves a big empty spot in the middle of your stomach," said owner Mike May.

Investigators initially thought the cause of the fire may have been electrical, an unfortunate accident that cost Bartlesville its landmark.  But, after they were able to sift through the rubble, they discovered meth-making materials.

"It looked like to be electrical in nature. We were finally able to get inside the building and do an in-depth investigation, and the fire patterns did not match what we would normally see in an electrical fire," said Bartlesville Assistant Fire Chief Bill Hollender.

Investigator Bill Hollender says the meth lab was found in a vacant area of second floor, above a restaurant.  The May Brothers Department Store closed last year, but the building was still home to eight tenants.

"Thankfully the fire department did an excellent job of putting the fire out, and were able to preserve a lot of our evidence that otherwise would have been lost," said Bartlesville Assistant Fire Chief Bill Hollender.

But, much of the building was a total loss.  While it may have been possible to accept an accidental fire, Hollender says the discovery of a meth lab is infuriating.

"It's bad enough to lose a building like that to natural causes or accidental causes, much less an illegal activity, drug activity, or arson. It's a horrible thing," said Bartlesville Assistant Fire Chief Bill Hollender.

Fire investigators have served six search warrants, and say they have several persons of interest.  No arrests have been made yet.