Three members of a San Bernardino family were killed Friday when they came into contact with the electric current from a 12,000-volt power line that had fallen into their backyard amid 50-mph winds.

Steven Vego, a 44-year-old plumber, went into the yard Friday morning after he and his family were jolted by two loud explosions. From inside the home, Kayli Vego saw her father step over the line and stumble to the ground.

She called to her mother, Sharon, who was in the frontyard putting out two fires apparently caused by falling power lines. Sharon sprinted to the backyard. But when she touched her husband, she collapsed as well. Her 21-year old son darted out next. He too tumbled to the ground when he touched one of his fallen family members.

According to a relative, Kayli, 17, and her 10-year old brother Steven Jr. watched in horror from inside the house and immediately called 911 at about 5:45 a.m.

When San Bernardino firefighters arrived, the grass was still sparking and smoldering, Capt. Mike Bilheimer said. They were initially unable to reach the victims because the line was still electrified. Crews from Southern California Edison arrived about 15 minutes later and the power was shut off.

Investigators from Edison, the San Bernardino City Fire Department, and other state and local agencies were still trying to determine what caused the high-voltage line to fall and how the three victims came into contact with it.

"We recognize this is a very difficult time for the family, friends and neighbors, and they have our deepest condolences," Edison President Ron Litzinger said at the scene.

Friends and relatives of the Vegos were outraged because a power line had fallen in the Vegos' backyard about three years ago and the family had questioned whether it was properly repaired.

Litzinger and another Edison official declined to comment on the accusations.

The family's next-door neighbor, Stella White, described hearing two explosions early Friday and said she saw fire glowing from the Vegos' backyard.

"It was a huge kaboom. I've never heard a noise like that before," said White, 79.

The dangling wire was still visible in the Vegos' backyard Friday afternoon and a large scorch mark marred the green grass.

Family and friends gathered to mourn the loss of the three victims, whom they described as kind and caring. Sharon Vego, 43, was a nurse, and her son, Jonathan Cole, was studying to become an emergency medical responder.