Dennis M. Crosby, one of Bing Crosby's twin sons by his first marriage, was found dead in his home on Saturday. He was 56 years old.
The police said yesterday that he died of a gunshot wound to the head, which was apparently self-inflicted.
A 12-gauge shotgun was found near a sofa, where Mr. Crosby's body lay. The case is being treated as a suicide, said Lieut. William Donovan of the Marin County Sheriff's office.
Dennis Crosby was the second of four sons born to Mr. Crosby and his first wife, Dixie Lee Wyatt Crosby, to commit suicide. Lindsay Crosby, the youngest son, shot himself to death in 1989 in Southern California at the age of 51.
The difficulties of growing up as a child of Bing Crosby were detailed in a 1983 book, "Going My Own Way," by the singer's eldest son, Gary, who portrayed his father as often cold and heartless.
Dennis Crosby, who was regarded as the quietest of the four brothers, nevertheless joined his brothers, including his twin, Philip, in a nightclub act during the late 1950's and early 60's. Known as the Crosby Brothers, they appeared on Ed Sullivan's show and other television programs and in clubs.