SANTA ROSA, Calif. -- A Colorado man who killed one man and wounded two of his relatives at his estranged wife's Santa Rosa home last week died Saturday evening of a self-inflicted gunshot wound, Santa Rosa police said.Walter Ross, 65, of Colorado Springs, died at Stanford University Medical Center in Palo Alto, police Lt. John Cregan said.Ross was armed with a 9mm semi-automatic handgun and a .357 revolver when he opened fire at a residence in the 400 block of Garfield Park Avenue around 8 p.m. on June 24. He fired as many as 15 rounds from the guns before shooting himself in the head, Cregan said.Bullets wounded his 41-year-old son and 4-year-old grandson and killed 43-year-old Timothy Gillaspie, a neighbor who tried to prevent Ross from entering the home. The family was having a dinner party and Ross's wife was not present at the time.There were nine people inside the house at the time. A woman hiding in a bathroom called 911 to report the shootings, police said.Gillaspie's heroic effort to try to prevent Ross from entering the home allowed the others to escape, Cregan said. Ross's wounded son and grandson have since been released from a hospital.Ross also rigged an explosive device to the door of his truck outside the Garfield Park Avenue home in Rincon Valley and he carried a bag with five more improvised explosive devices into the home, police said.Detectives who traveled to Colorado Springs last week searched Ross's residence and spoke to members of his family to understand his motive and activities before the shootings, Cregan said.Detectives found evidence including written documents that showed Ross's "meticulous, calculated and pre-meditated" plan for revenge on his estranged wife, his son and his son's family before killing himself, Cregan said."He perceived they supported his estranged wife," Cregan said this morning.Ross and his estranged wife, who has not been identified, were separated for two years, and their divorce was to become final this month, Cregan said.