The Sonoma County Sheriff’s Office is hoping a blurry photo might help them track down a bicyclist involved in a Friday morning scuffle with two Kenwood residents, including a 68-year-old woman who the man pushed to the ground, authorities said.

The woman wasn’t badly hurt, but the cyclist’s rude behavior amounts to simple battery and elder abuse if the details conveyed by the woman, her husband and two neighbors are accurate, authorities said.

The incident occurred around 11:20 a.m. Friday at Warm Springs Road and Los Guilicos Avenue, where Kenwood residents Robert and Jacalyn Pierce were walking in their neighborhood and stopped to talk with a neighbor, Sheriff’s Sgt. Greg Piccinini said.

They were standing partially in the roadway when the cyclists turned from Warm Springs Road and brushed the back of Robert Pierce, who reportedly yelled at the man to “get a bell” for his bike, Piccinini said.

The cyclist then dismounted and walked back toward them, meeting face-to-face with Jacalyn Pierce who had left her husband’s side and walked toward the bicyclist yelling something like, “Yeah, get a bell,” Piccinini said. Soon, they were in each other’s faces, the man’s helmet bumping Jacalyn Pierce’s head before he pushed her down with both hands, witnesses said.

Another neighbor watching through her window took some photos with her phone as the cyclist got back on his bike and rode away. The Pierces, meanwhile, got in their car and called law enforcement while trying to locate the cyclist.

While deputies were responding from the other end of the Sonoma Valley and from the main office in Santa Rosa, the Pierces caught up with the cyclist and followed him part way through Oakmont, where he entered Trione-Annadel State Park at the Stone Bridge Trail, authorities said.

Responding deputies checked the area but were unable to locate him. Witnesses to the incident said they had seen him cycling in the area from time to time. He was described as a white man in his 50s with a gray beard. He was wearing a red biking shirt and red helmet, with black cycling pants and riding a dark-colored road bike.

Jacalyn Pierce complained of pain but refused medical treatment, Piccinni said.

Anyone with information about the case is asked to contact Sheriff’s Deputy William Badour atWilliam.Badour@Sonoma-County.org or through sheriff’s dispatch at 707-565-2121.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.