A Marin County attorney with a taste for freshly caught abalone died Sunday while diving with his son on the Sonoma Coast.

Brian Dinday, 62, of San Rafael was pulled from the water by a Sonoma County Sheriff's Department helicopter rescue crew after 1 p.m. at Horseshoe Cove in Salt Point State Park, authorities said.

Whether Dinday drowned or suffered a medical condition had not been determined on Monday, the coroner's office said.

Dinday's son, Matthew, 30, who was diving with his father and watched him get swept away from the shore in rough surf was too distraught to talk to anyone Monday, said Dinday's wife, Mary.

"He was doing what he loved," Mary Dinday said of her husband, who started abalone diving in the 1980s and just resumed the sport last year. "I don't think that's any consolation."

The men, described as careful divers and strong swimmers, were caught in heavy waves that started quickly and took them by surprise, Mary Dinday said.

Matthew Dinday reached the shore and shed his flippers, thinking his father was right behind him. "He realized his father was in trouble," Mary Dinday said.

Matthew went back into the water but was unable to reach his father, she said.

The helicopter crew found Brian Dinday floating face down close to the rocky shore, officials said.

Dinday, a criminal defense lawyer and father of four grown children, was the fourth person to die this year in connection with abalone diving off the Sonoma and Mendocino county coasts.

In 2008, eight people died while abalone diving off the North Coast.

One of Brian Dinday's many posts on the Web site Epinions.com described the hazards of diving 25 feet down in frigid water, holding his breath and wary of becoming fatally entangled in kelp.

"Only once did I come close to buying the farm, and it was due to nothing more than rough water," he wrote in a January, 2000 post.

Paul Bradley, the sheriff's helicopter pilot, described the water in Horseshoe Cove Sunday afternoon as "very rough."

Mary Dinday said her husband and son had sometimes made the two-and-a-half-hour drive to the northern Sonoma coast and returned home when the ocean conditions were poor. "They were not reckless," she said.

The Dindays, who married in 1974, moved from New Jersey to California in 1977 and had lived in San Rafael for more than 30 years. Brian Dinday was a criminal defense lawyer with offices in San Rafael and San Francisco.

A writer and handyman, Dinday fashioned titanium pry bars to dislodge abalone from underwater rocks for himself and his son. Mary Dinday, who works at a San Rafael securities firm, said she was worried when her husband resumed diving last year.

"He was passionate about it," she said. "I wouldn't do it for anything in the world."

On Saturday night the couple celebrated Brian Dinday's 62nd birthday by seeing the movie "2012." "He loved it; I hated it," she said.

Brian Dinday spoke by telephone to his four children on Saturday.