EHRENBERG, Ariz —  Four firefighters and two others have been arrested on suspicion of starting between 15 and 20 fires in western Arizona to make money.

La Paz County sheriff's Lt. Glenn Gilbert says the fires were set between last January and last week. They occurred in abandoned trailer homes, open land and in expensive haystacks owned by farmers.

No one was hurt in the fires but the most costly destroyed a $200,000 haystack.

The investigation began months ago when a sheriff's officer thought one fire was suspicious and only recently pointed to the firefighters and two acquaintances.

Gilbert says the firefighters admitted to starting the blazes to make money. They get $10 an hour per fire. Haystack fires can last days.