The officer was conducting a foot patrol near the Upper San Leandro Reservoir at about 6:50 p.m. Monday when two suspects fired an assault rifle at him.
Police said the officer returned fire and took cover, and was not injured in the attack. He called for emergency assistance and was safely retrieved from the scene in a park district police armored rescue vehicle, police said.
Alameda County SWAT teams and other local jurisdictions helped regional parks police search the expansive watershed space on Tuesday and Wednesday, when they finally found the crime scene, police said today.
Evidence of the firefight -- including expended firearms ammunition casings from a high-powered assault rifle -- was sent to a crime lab for processing, police said.
The department said aerial surveillance has uncovered at least one active marijuana cultivation site, although it is not clear yet if the shooting was related to the grow.
Police had not identified any suspects as of today and were asking anyone with information to call the department at (510) 881-1833.
