Five people found slain in a San Francisco house were members of an extended family of Chinese immigrants, a woman who identified herself as a relative said. The woman, who would give her name only as Lena, told the San Francisco Chronicle she had been trying to call relatives she feared were among the dead and had not been able to reach them. The bodies were discovered at about 7:45 a.m. PDT Friday. Police spent the day searching the house, trying to determine what had happened. Police Commander Lyn Tomioka said investigators had been unable to determine if the deaths were a murder-suicide or a mass killing. She said the scene was \"very difficult\" and police were still unsure whether the dead had been shot or stabbed. \"The medical examiner is going to sort out for us the cause of death,\" Tomioka said. \"We\'re looking at everything, but we just can\'t determine what happened yet.\" A relative who came to the row house early Friday noticed a body in the front hall and two in the garage, police said. Two more were in the back.