VANCOUVER, WA (MyBellinghamNow.com) – Authorities are investigating after hundreds of ballots in southwest Washington were destroyed in a fire early Monday, Oct. 28.

One ballot box in Vancouver, WA and one in Portland, OR were set on fire using incendiary devices that were pushed inside the box.

A fire suppressant inside the drop box in Portland protected nearly all the ballots, leaving only three damaged. But Clark County Auditor Greg Kimsey told the Associated Press that the fire suppression system in the Vancouver drop box “wasn’t effective” for some reason.

Police said during a news conference that they believe the two fires were connected and that they were also connected to another ballot box fire in Vancouver on Oct. 8. They have identified a suspect vehicle after surveillance images captured a Volvo stopping at the Portland drop box just before the fire was discovered

Vancouver is in Washington’s 3rd Congressional District. It’s the site of what is expected to be one of the closest U.S. House races in the country, between first-term Democratic Rep. Marie Gluesenkamp Perez and Republican challenger Joe Kent.