CCTV captures the moment an unknown suspect drops an explosive device into a Portland ballot box seconds before it explodes.
The incident, which is one of several that occurred in Oregon and Washington state ahead of the 2024 presidential election, occurred on 28 October.
Investigators described the suspect as a White male between 30 and 40, who is balding with short hair. It is believed he has some experience with metalwork and welding.
Surveillance footage shows an individual driving up to the box in an early 2003 to 2004 Volvo S-60 sedan, described to be dark, with dark wheels and a light-coloured interior.
The FBI is offering a reward of up to $25,000 (£19,000) for information leading to the identification, arrest, and conviction of the suspect responsible for the crimes.