Police say riot gear and a uniform are among items stolen from a storage locker at the Concord BART station.
It is believed the theft occurred sometime between 2 p.m. Monday and 10 a.m. Tuesday, according to police.
The loss, which amounts to $1,000, includes a riot helmet, gas mask, a BART police jacket with patches, uniform pants and a radio battery with a charger, police said.
The transit agency said it is now stepping up security efforts, especially with the upcoming Super Bowl and related festivities.
The FBI is also working the BART to track down the thief.
"Very much a concern for us," FBI Special Agent in Charge DJ Johnson said of the stolen police gear. "We're taking it very seriously."
The FBI is also trying to determine if the items could pose a threat during the Super Bowl.
"Absolutely no indication yet, but we are looking just to make sure that's the case," Johnson said.
An investigation is ongoing. No other information was immediately available.