A district attorney's investigator who shot five family members in the head as they slept before killing himself had no apparent marital or financial problems, police and relatives said.

Investigators are still baffled about why David McGowan (search), a 44-year-old investigator for the Riverside County (search) district attorney's office, killed his wife, mother and three children early Tuesday.

"The million-dollar question is why someone with such a reputable record would one day wake up, and the next thing you know, you've killed your entire family," District Attorney Grover Trask (search) said Wednesday. "We've tried to rationalize why — did he have financial, work, alcohol or drug issues? But we haven't found any of that."

Investigators searching McGowan's sprawling, two-story ranch home about 100 miles southeast of Los Angeles found the typed lyrics of the Los Lonely Boys (search) song "Heaven" next to his computer and a note that read, "Woe is me. I'm looking forward to seeing you in the next life."

The song is about being trapped and lost in life, and McGowan's note was on the same sheet of paper as the lyrics.

Based on a trail of bloody sock prints, investigators determined that McGowan used his duty weapon to kill his wife Karen, 42, and mother Angelia, 75, upstairs, then went downstairs and killed the children — son Chase, 14, and daughters Paige, 10, and Rayne, 8.

Each victim was shot once in the head, except for his wife, who was shot twice, Riverside County Sheriff Bob Doyle said. David McGowan was found near the front door, with a phone and gun nearby.

Deputies were sent to the ranch after someone from the house — likely David McGowan — called 911 at 4:33 a.m. Tuesday. The call begins with the sharp crack of an apparent gunshot and ends with rustling and several loud thumps — apparently McGowan and the telephone falling to the floor.

No words were spoken during the brief call.

Relatives and friends said they saw no marital problems between McGowan and his wife, a stay-at-home mom and former firefighter who ran a small tree-trimming operation from the couple's home.

"All I know is he loved his family dearly. He was a very good father and he loved his wife. They were very close," McGowan's sister, Sandy Curl, told the Los Angeles Times.

"Dave in many ways was so perfect that you think this has got to be a mistake," said Curl's husband, Alan. "He adored his kids. He loved his mother. It's a mystery to us all."

Colleagues said McGowan, who helped prosecutors prepare cases for trial, gave no clues that anything was wrong.

A model employee, he had just returned from a week's vacation and had received an outstanding review, said Ingrid Wyatt, a spokeswoman for the district attorney's office. He had a normal workload, she said.

"He reported to work every day, just like normal. We weren't aware of any financial or personal problems within the family," she said. "That's why we're all so shocked about the situation."