Unconscionable as it is—particularly in the wake of the destructive Fourmile Fire—it appears someone is purposefully trying to spark wildfires along the Front Range. Arson investigators, including federal agents, are looking into a string of fires in northern Colorado described as suspicious, including one that burned about 1,000 acres and a vacant house south of rural Kersey late last week, according to The Greeley Tribune.

Early Saturday, three other grass blazes were ignited west of Greeley, notes 9News.

The Colorado Bureau of Investigation has placed one of its two accelerant-sniffing dogs at the scenes of the fires, after the Weld County Sheriff’s Office called for assistance, writes The Denver Post.

Meanwhile, prosecutors have charged Joel Ledermann for his alleged role in starting the Reservoir Road fire west of Loveland. Ledermann is suspected of burning branches and other debris that got out of control and consumed 750 acres and two homes. He will go before a judge on charges of fourth-degree arson, reports the Loveland Reporter-Herald.