S.F. cop knocked out by man allegedly building shotgun

A man attempting to assemble a shotgun on the streets of San Francisco knocked a police officer unconscious Sunday evening, leaving the cop with a concussion, before the man was arrested, officials said.

Officers responded to reports of a man, later identified as 23-year-old transient Joshua Boling, trying to put together a shotgun in front of a restaurant on the 1700 block of Octavia Street around 10:30 p.m., said Officer Grace Gatpandan, a police spokeswoman.

The first officers on the scene approached and a struggle ensued, Gatpandan said, with Boling allegedly grabbing one of the officers around the waist and slamming him into a wall, knocking him out.

Multiple officers responded as the struggle continued and Boling was arrested a short time later, Gatpandan said, but not before he struck another officer in the face.

The unconscious officer was taken to San Francisco General Hospital, where he was treated for a concussion and released. The officer who was hit in the face suffered minor injuries, Gatpandan said, but did not require treatment.

Boling was arrested on suspicion of resisting arrest and battery on a peace officer, among other lesser charges, and the shotgun was recovered from the scene, Gatpandan said.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale