TAHLEQUAH, Oklahoma - There have been 12 arson fires in Tahlequah since January, and the chief said the targets are getting bigger.

What was a shed a few days ago is now a charred pile of wood and the fire that damaged it was one of the suspected arsonist's the most recent.

The fire chief is sending a warning to whoever is responsible.

Arsonists have set fire to two of the Bigby family properties - the shed and a house being used for storage.

Resident Luke Bigby said, "It's people's property, they are setting fire to it and burning it down and it's just kinda real bad. I had to sit out here and make sure nothing was broken in, or stolen or making sure no one came back trying to steal things."

The smoke is gone but the damage remains, as does the question ‘why?' The Tahlequah police and fire department are working on answering that.

Fire Chief Ray Hammons said, so far no one has gotten hurt, but since January the arsonist has upped their game - from grass and trash bin fires to homes.

“Oh yeah we're sure it's someone setting these things on fire, not a coincident that this many have happened in this area," Hammons said.

He said the 12 fires have been in walking distance of each other, leading fire investigators to believe it's one person or one group responsible.

"Certainly something we're concerned about and trying to investigate to see if we can find out what's going on," Hammons said.

There are a few leads but nothing concrete. Luke said since the last fire he's been keeping watch to make sure the arsonist doesn't come back.

As for the shed, people have already stripped that of the valuable metal that was left over.

Bigby said, "Hopefully that the people get caught before anything else really bad happens,”

Fire crews aren't releasing the source of the fires but believe, in all of the cases, the ignition sources may be the same.

If you have information on who may be responsible for the fires you're asked to contact law enforcement.