Bronze plaques are going missing from the exterior walls of San Diego County libraries. Sheriff’s investigators want to know who did it and are hoping tipsters can help solve the case.

The first plaque disappeared in late September from the Alpine library branch, Sgt. Michael Mascarenas said. The Rancho San Diego branch was hit about two weeks later, on Oct.13.

Sheriff's investigators released surveillance camera images linked to the Oct. 17 theft of a plaque from the exterior wall of the county library branch in Imperial Beach. Plaques have gone missing from five county library branches since Sept. 30. (Courtesy of San Diego County Sheriff's Office)Sheriff’s investigators released surveillance camera images linked to the Oct. 17 theft of a plaque from the exterior wall of the county library branch in Imperial Beach. (Courtesy of San Diego County Sheriff’s Office)

Days later saw a heist from the Imperial Beach branch. Lemon Grove’s branch was next. In late October, the 4S Ranch branch joined the list of victims.

Mascarenas said it appears the plaques were pried from the walls. He said it’s more than likely they were taken to a recycling center to be sold as scrap and melted down.

Investigators believe the same person is responsible for at least the thefts in Rancho San Diego and Imperial Beach, and possibly all five thefts.

Sheriff's investigators released surveillance camera images linked to the Oct. 17 theft of a plaque from the exterior wall of the county library branch in Imperial Beach. (Courtesy of San Diego County Sheriff's Office)Sheriff’s investigators released surveillance camera images linked to the Oct. 17 theft of a plaque from the exterior wall of the county library branch in Imperial Beach. Plaques have gone missing from five county library branches since Sept. 30. (Courtesy of San Diego County Sheriff’s Office)

The Imperial Beach plaque, valued at around $4,500, was taken just before 11 p.m. Oct. 17 from the library branch at Imperial Beach Boulevard and Eighth Street. Investigators said the thief arrived in a white 2005-2010 Chevrolet Silverado. The person placed the plaque in the truck bed and took off.

Sheriff's investigators released surveillance camera images linked to the Oct. 17 theft of a plaque from the exterior wall of the county library branch in Imperial Beach. Plaques have gone missing from five county library branches since Sept. 30. (Courtesy of San Diego County Sheriff's Office)Sheriff’s investigators say this man is suspected in the Oct. 17 theft of a plaque from the exterior wall of the county library branch in Imperial Beach. (Courtesy of San Diego County Sheriff’s Office)

Sheriff’s investigators described the suspect in that instance as a bald White man in his 40s. He wore a dark-colored sweatshirt, gray shorts and dark-colored sneakers. The Silverado is a single-cab truck with a steel front bumper.

Authorities asked that anyone with information on the identity or location of the suspect or the truck call the Imperial Beach Sheriff’s Substation at 619-498-2400.

Anonymous tips can be left by calling Crime Stoppers at 888-580-8477 or online at sdcrimestoppers.org. There is a reward of up to $1,000 for information that leads to an arrest in the case.