The search continued Monday for a man whose reported attack on a woman near a remote reservoir used by the Sonoma Developmental Center has spotlighted illegal access to the site and the apparent rampant disregard for dog leash laws.

Sunday's attack involving two dog walkers whose pets were unleashed occurred on property owned by the state, and not at Sonoma Valley Regional Park, as authorities originally reported. The adjacent properties are near Glen Ellen, sandwiched between Arnold Drive and Highway 12.

A 60-year-old woman who was walking her dog Sunday near the reservoir, also known as Lake Suttonfield, reported that she was assaulted by a man after their dogs got into a fight. The woman said her assailant wrapped a dog leash around her neck, knocked off her glasses, threw her cellphone in the lake after she threatened to take his photo and kicked her dog several times before he took off running.

Sonoma County Sheriff's Sgt. Dave Thompson said Monday that deputies were following several promising leads, and that a violent crimes detective had been assigned to the case because of the circumstances.

"We want people to use our parks and recreation areas without fear of running into a loose cannon like this guy," Thompson said.

Visitors at the regional park Monday expressed shock at the assault.

"I'm totally blown away," said Cynthia Beck of Oakmont as her dogs romped in a fenced-in area reserved for off-leash play. "The dog owners that come to this park seem to be extremely responsible."

But Sunday's attack appears to have exposed the frequency with which people illegally access the state's property and flout leash laws there and at the adjacent county park, which spans 162 acres.

Sandy Martindale, a former volunteer with the park's Mounted Assistance Unit who was headed out Monday for a ride, said problems are inevitable because of the number of dogs running free in the area.

She recalled one instance in which a dog came bounding over a hill and spooked a horse, causing the animal to spin and throw its rider. Martindale said the woman "won't come here anymore."

Lake Suttonfield on the state property side is supposed to be off-limits to the public. A spokeswoman said the developmental center's Office of Protective Services patrols the area daily, and signs inform visitors of the prohibition on trespassing and swimming.

But people routinely ignore the rules to access the property. Authorities said Monday that the victim in Sunday's attack was on state property the entire time, after she parked on Arnold Drive across from the center's animal farm. Her assailant also fled in that direction.

The woman had a medium-sized dog believed to be a border collie. Her assailant was thought to have a reddish-brown and white Australian shepherd. The man was described as white and in his 50s, about 6-feet tall, with a thin build, gray hair and a brown and gray beard. He wore a red baseball cap, blue vest and shorts with a fanny pack.

At the county park, dog owners are required to keep their pets on a leash of no greater than six feet in length outside of the fenced-in area. Meda Freeman, a spokeswoman for county parks, said rangers frequently issue verbal warnings and can also cite people, but she did not have access to specific numbers Monday.

Diane Askew of Kenwood acknowledged that she often allows her dog to run free at the park. She defended the practice because of her dog's age and limited mobility, and because she said people usually are good about putting their dogs on a leash when they see another dog approaching.

She said the off-leash area is "not fun for either of us. It may be fun for a puppy, but for a 12-year-old (dog), he just wants to sit down."

She also wondered whether the victim of Sunday's attack may have embellished her story. "Everyone I've met up here is wonderful. It's hard for me to imagine a guy wrapping a leash around someone's neck," she said.

Thompson said the fact the woman's earrings were damaged, in addition to her glasses being ripped from her face, supports her version of events. He said other witnesses reported seeing the man hustling out of the park.

A Sonoma man who gave his name as Cliff said Monday at the park that he understands how someone could get upset by an attack on their dog. But he said when such a thing happens, particularly in a rural setting, people should become partners in "de-escalating the situation."

"It sounds like someone has some issues," he said of the suspect in Sunday's attack.

You can reach Staff Writer Derek Moore at 521-5336 or derek.moore@pressdemocrat.com. On Twitter @deadlinederek.