Stanwood Fred Elkus, 75, was jailed on $1 million bail after police say he shot Dr. Ronald Franklin Gilbert multiple times on Monday at a medical office in Newport Beach, an affluent city in suburban Orange County.
Police would not say if the 52-year-old Gilbert was Elkus' doctor. The urologist appeared to be the only target of the attack, police spokeswoman Kathy Lowe said.
Elkus, who has an initial court hearing Wednesday, was plagued by prostate troubles and was upset by a surgery that left him running to the bathroom constantly, sometimes in mid-conversation, neighbors said.
"One day we were talking about other things outside and he says, 'Oh hold it right there!' and he was rushing to his house and when he came back, he said, 'I have a problem with my prostate,'" recalled Miguel Soto, who lives across the street.
"He said, 'I had surgery and now I am worse than before the surgery.'"
Soto said Elkus never named his doctor, and Soto did not know if it was Gilbert.
A few weeks ago, Elkus said he would be away from home because he was checking into a hospital again, but when Soto saw him last week, he didn't mention his health.
Neighbor James Lord said Elkus mentioned Sunday that "he wasn't going to be around much longer."
"I told him, 'No Stan, you're gonna outlive me,'" Lord said.
Detectives recovered a handgun at the scene of the shooting and found additional evidence at Elkus' home in Lake Elsinore, but police declined to provide more details.
At Gilbert's home in Huntington Beach, mourners arrived as distraught family members and a rabbi went in and out of the house just blocks from the water. The family declined comment and asked a reporter to leave.
Gilbert dealt with general urology, sexual dysfunction and related surgical techniques including vasectomies, bladder and prostate cancer, according to his biography on the website of the Orange Coast Urology Group, which he joined in 1993.
One of his specialties involved using a laser to vaporize prostate tissue blocking the urinary tract.
He decided to become a doctor mainly because his late father was a doctor, the biography said, adding that Gilbert had been a stockbroker and a singer in a rock band.
He had worked for 20 years at Hoag Hospital and was its former urology chief.
Dr. Jeffrey Lauber, a dermatologist, said he frequently referred patients with cancer symptoms to Gilbert.
"He's the best there is," Lauber said. "Not only is he a very good urologist, he's a pillar of the community."
Jablon reported from Los Angeles. AP Writer Shaya Tayefe Mohajer in Los Angeles and AP Researcher Rhonda Shafner in New York City contributed to this report.