Police say the man behind the ballot box fire may be planning more attacks.

ALANNA DURKIN RICHER and CLAIRE RUSH

PORTLAND, Ore. (AP) — A man suspected of arson at ballot boxes In Oregon and Washington states, he is an experienced locksmith and may be planning more attacks, authorities said Wednesday.

Investigators believe the man who planted incendiary devices in ballot boxes in Portland, Oregon, and nearby Vancouver, Washington, had “extensive experience” in metal fabrication and welding, Portland Police Bureau spokesman Mike Benner said.

The way the devices were constructed and how they were attached to the metal boxes demonstrated that professionalism, Benner said.

Authorities described the suspect as a white male, between 30 and 40 years old, who is balding or has very short hair.

Police previously reported surveillance video showed a man driving a black or dark Volvo S-60 from 2001–2004. The car did not have a front license plate, but had a rear license plate with unknown letters and numbers.

The incendiary devices were marked “Free Gaza Strip,” according to a law enforcement official who spoke to The Associated Press on condition of anonymity because they were not authorized to discuss an ongoing investigation.

A third device installed in another mailbox in Vancouver earlier this month also said “Free Palestine” in addition to the words “Free Gaza Strip,” the official said.

Investigators are trying to determine the perpetrators and motives for the alleged arson. destroyed or damaged hundreds of ballots at a drop box in Vancouver on Monday when the box’s fire suppression system did not work properly. The official said authorities were trying to determine whether the suspect actually had pro-Palestinian views or was using the message to create confusion.

Surveillance images captured the Volvo pulling up to the crate in Portland just before nearby security officials discovered a fire inside the crate on Monday, Benner said. The early morning fire was quickly extinguished thanks to the box’s fire suppression system and a nearby security guard, according to police. Only three ballots inside were damaged.

The burned ballot box in Vancouver also had a fire suppression system inside, but it failed to prevent hundreds of ballots from burning, said Greg Kimsey, the longtime elected auditor in Clark County, Washington, which includes Vancouver. Kimsey said Tuesday that the exact number of ballots destroyed was unknown and that about 475 damaged ballots had been removed from the ballot box.