OAKLAND (AP) — The California Highway Patrol said it told local police that plainclothes officers would mingle with protesters demonstrating against police brutality on the east side of the San Francisco Bay, but Oakland Police Department officials said they were not notified.

Oakland Police said the CHP never informed the department that officers wearing civilian clothes would attend the demonstrations held in their city over the last several weeks, the San Francisco Chronicle reported Thursday.

A plainclothes CHP officer brandished his handgun at protesters Dec. 10 after his partner was exposed as a police officer and knocked to the ground. The CHP officer didn’t fire the weapon but said he pulled it from its holster out of fear for his partner’s safety.

The CHP said plainclothes officers were assigned to gather information that would help prevent protesters from entering freeways.

Avery Browne, chief of CHP’s Golden Gate Division, defended the officers’ actions and said the agency has had plainclothes officers at these demonstrations since they began Nov. 24, to gather information that would prevent protesters from entering and blocking freeways, a core tactic of the movement against racial injustice and police brutality.

The march that night, as on many other nights, moved between Berkeley and Oakland. Browne said the Oakland Police Department was aware of the CHP’s plainclothes operations, and that CHP had an officer in Berkeley’s emergency operations center.