A man and a woman were found stabbed to death and a longtime family friend found their bodies on Thursday in Diamond Bar, authorities said.
Detectives were sent to the 3300 block of Bent Twig Lane at about 9:45 a.m., the sheriff's department reported.
Chao Ho Chen said he got a call from family members asking him to check on the two-story home.
When he went inside he found the two bodies of his married friends -- the husband, 60, and the wife, 57.
"She was a really nice person," Student Annabelle Yeh said of the woman, who was her former teacher. "She was really successful and I don't know why anyone would want to murder her.
Chao said both of them were on the ground on the first floor and it was a gruesome sight.
"They are a very nice couple, so I can't imagine who would do this," said Kevin Lu, a family friend.
Investigators said it appears both victims were stabbed to death, but officials are waiting for confirmation from the coroner.
Chao said it didn't appear the house had been broken into and nothing appeared stolen.
Investigators also said the home did not appear to be ransacked and they are not ruling out the possibility that it could be a murder suicide.
No arrests were reported.
