POLAND, Maine (NEWS CENTER) — State fire investigators on Monday said they still don't know who started the fires Sunday night that destroyed six big trucks at the same trucking company, causing an estimated $750,000 in damage.

They are calling it a case of "coordinated arson."

The fires were apparently set at two locations for the R.C. Moore trucking company — one in Poland, where four trucks were destroyed, and another in Scarborough, where two trucks were destroyed and two damaged.

The fires were spotted within three minutes of each other, shortly before 8:20 p.m. Sunday. No one was hurt.

State fire investigators spent much of Monday searching through remains of the trucks, looking for clues. They are also examining surveillance camera footage from the truck lots and some neighboring businesses. Investigators said they have taken brief looks at that video but will need a number of hours to review all of it.

» RELATED: Fires destroy tractor-trailer trucks in two towns

State Department of Public Safety spokesperson Steve McCausland said this kind of arson is highly unusual for Maine.

"[T]o have two incidents at the same company, minutes apart, I can't recall anything remotely similar to what we’re dealing with here," McCausland said

Company officials and workers said the fires are unsettling. Company owner Kelly Moore said R.C. Moore operates more than 200 trucks, so there was little disruption to business. However, he, too, said it was stressful for everyone because they have no idea who is targeting the business. Among other clients, R.C. Moore hauls water for Poland Spring, a business that is sometimes controversial. Moore, however, said he does not think the fires are related to that work.

"I don’t think that’s anything at all," Moore said. "For all in all Poland Spring and us and all the trucking companies try to work with all the communities, so I don’t see that at all.”

Fire investigators said they are looking for more information on a strange car that was seen Sunday afternoon in the Poland lot. McCausland described it as a gray sedan, with a green driver’s door and amber light on the roof. He said it turned around in the trucking company lot, but when an employee came out to check on it, "the car abruptly drove off."

McCausland said they don’t know if there is any connection between the car and the fires, but they want to find out and are asking for public help to locate the car and driver.

Fire investigators said they expect to finish examining the debris at Poland by the end of the day Monday, but have more work to do in Scarborough. And they said there are a number of other interviews to do, as well as further examination of the surveillance video.