WASHINGTON (AP) — Incendiary devices found at the scene of ballot drop box fires in Portland, Oregon, and nearby Vancouver, Washington, this week were marked with the message "Free Gaza," according to a law enforcement official.

A third device placed at a different drop box in Vancouver earlier this month also carried the words “Free Palestine” in addition to “Free Gaza,” said the official, who spoke on the condition of anonymity because they were not authorized to discuss an ongoing investigation.

Investigators are trying to identify the person responsible and the motive for the suspected arson attacks, which destroyed hundreds of ballots at one location in Vancouver on Monday when the drop box's fire suppression system didn't work as intended. Authorities are trying to figure out whether the person who left the devices actually had pro-Palestinian views or used the message to try to create confusion, according to the official.

Surveillance images captured a Volvo pulling up to a drop box in Portland just before security personnel nearby discovered a fire inside the box on Monday, according to Portland Police Bureau spokesman Mike Benner.

The early-morning fire at the drop box in Portland was extinguished quickly thanks to a suppression system inside the box as well as a nearby security guard, police said. Just three of the ballots inside were damaged.

The ballot box in Vancouver that burned also had a fire suppression system inside, but it failed to prevent hundreds of ballots from being scorched, said Greg Kimsey, the longtime elected auditor in Clark County, Washington, which includes Vancouver. Kimsey said Tuesday that the exact number of destroyed ballots wasn't known, and that about 475 damaged ballots had been retrieved from the box.

Election staff on Wednesday planned to sort through the damaged ballots for information about who cast them, in the hopes that those voters can be given replacement ballots. Kimsey urged voters who dropped their ballots in the transit center box between 11 a.m. Saturday and early Monday to contact his office for a replacement ballot.

Authorities said at a news conference in Portland on Monday that enough material from the incendiary devices was recovered to show that the two fires were connected — and that they were connected to an Oct. 8 incendiary device at a different ballot drop box in Vancouver. No ballots were damaged in that incident.

Voters in Washington are encouraged to check the status of their ballots at www.votewa.gov to track their return status. If a returned ballot is not marked as "received," voters can print a replacement ballot or visit their local elections department for a replacement, the secretary of state's office said.

Police tape surrounds a ballot drop box damaged by a fire on Monday, Oct. 28, 2024, in Vancouver, Wash. (Monika Spykerman/The Columbian via AP)

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Police tape surrounds a ballot drop box damaged by a fire on Monday, Oct. 28, 2024, in Vancouver, Wash. (Monika Spykerman/The Columbian via AP)

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A voter drops off a ballot for the 2024 election in a newly installed drop box at the Multnomah County Elections Division office on Monday, Oct. 28, 2024, in Portland, Ore., after the pervious drop box was damaged. (AP Photo/Jenny Kane)

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A damaged bin that was in a ballot drop box is displayed at the Multnomah County Elections Office on Monday, Oct. 28, 2024, in Portland, Ore. (AP Photo/Jenny Kane)

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Election workers collect ballots from a newly placed ballot drop box outside the Multnomah County Elections Division office on Monday, Oct. 28, 2024, in Portland, Ore. (AP Photo/Jenny Kane)

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A damaged ballot drop box is displayed during a news conference at the Multnomah County Elections Division office on Monday, Oct. 28, 2024, in Portland, Ore. (AP Photo/Jenny Kane)

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A fire-damaged ballot drop box bin is seen next to the drop box during a news conference at the Multnomah County Elections Division office on Monday, Oct. 28, 2024, in Portland, Ore. (AP Photo/Jenny Kane)

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A person drops off their 2024 election ballot at a newly installed drop box outside the Multnomah County Elections Division office on Monday, Oct. 28, 2024, in Portland, Ore. (AP Photo/Jenny Kane)

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