PORTLAND, Ore. (AP) — The FBI said Wednesday it is offering up to $25,000 as a reward for information about the suspect behind recent ballot box fires in Oregon and Washington state.

Authorities believe a male suspect that may have metalworking and welding experience was behind three ballot drop box fires in Portland and Vancouver, Washington, last month, including one that damaged hundreds of ballots in Vancouver about a week before Election Day. They have described him as a white man, age 30 to 40, who is balding or has very short hair.

The FBI specifically asked for help identifying the suspect’s car. Surveillance cameras captured images of a dark-colored, early 2003 to 2004 Volvo S-60 sedan, but at the time of the two most recent ballot box fires on Oct. 28 in Portland and Vancouver, it had a fraudulent temporary Washington license plate on the rear and no front plate, the bureau said.

“No detail is too small. No tip is too minor. If it relates to a Volvo matching our description, we want to hear about it,” Gregory Austin, acting special agent in charge of the FBI’s Seattle field office, told reporters Wednesday. “The FBI’s mission is to protect the American people and uphold the Constitution. These three ballot box fires were an attack on both.”

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William Brooks, acting special agent in charge of the FBI’s Portland field office, said multiple local law enforcement agencies were providing resources, such as investigators, analysts and bomb technicians, to help the investigation.

“Voters in both Oregon and Washington deserve answers in this case,” Brooks said. “Their votes and their voices matter, and we can’t allow one person’s violent actions to infringe on their rights.”

Investigators are trying to identify the person responsible and the motive for the suspected arson attacks.

The Oct. 28 incendiary devices were marked with the message “Free Gaza,” according to a law enforcement official who spoke to The Associated Press on the condition of anonymity because they were not authorized to discuss an ongoing investigation. A third device placed at a different drop box in Vancouver on Oct. 8 also carried the words “Free Palestine” in addition to “Free Gaza,” the official said.

Authorities are trying to figure out whether the suspect actually had pro-Palestinian views or used the message to try to create confusion, the official said.

A fire suppression system in the Portland drop box prevented most of the ballots from being scorched. Just three of the ballots inside were damaged.

The ballot box in Vancouver also had a fire suppression system inside, but it failed to prevent hundreds of ballots from being damaged during the Oct. 28 drop box fire. Elections staff were able to identify nearly 500 damaged ballots retrieved from the box, according to the Clark County auditor’s office.

No ballots were damaged during the previous drop box fire in the city on Oct. 8.

In response, the county auditor’s office increased how frequently it collects ballots and changed collection times to the evening to keep the ballot boxes from remaining full of ballots overnight when similar crimes are considered more likely to occur.