Speeding Drivers Failed to Stop for Fatal Crash : Accident: Authorities are searching for a dark blue Mercury Capri or a Chevrolet Chevette, which witnesses say caused the wreck on the Santa Ana Freeway in Irvine that killed two people Saturday.

A spectacular accident that killed two young people and seriously injured another two Saturday night on the crowded Santa Ana Freeway was caused by the drivers of two other cars racing at speeds up to 75 m.p.h., authorities said Sunday.

Both drivers left the scene without stopping after one of the speeding vehicles sideswiped a 1987 Ford Bronco, causing the driver to swerve sharply and the vehicle to overturn several times and eject three passengers. The drivers of the racing vehicles are being sought by police.

The dead were identified Sunday as Jennifer Twohy, 19, and William Baughn, 21, both of Placentia.

A friend of Twohy’s family said the young woman was a student at Fullerton College whose family “will miss her deeply.” Family members were distraught and declined to comment.

Jessica Barnes, 18, who was seated in the middle front seat of the Bronco, said late Sunday that she and her five friends were headed to Del Mar and ultimately to Tijuana, where they hoped to spend some time dancing at clubs.

She said most of the people in the group had been friends since they attended El Dorado High School. She had known Twohy, whom she considered one of her closest friends, since kindergarten.

“She was the greatest person--always happy, always smiling--that’s just Jen,” Barnes said. Twohy loved to dance and play soccer and had been studying to be a physical therapist, Barnes said.

Baughn, she said, was the boyfriend of the Bronco driver, Katherine Siedentop, 20, who sustained minor injuries in the wreck.

He was “very caring. . . . I thought my friend [Katherine] was lucky to have him,” Barnes said.

Barnes said she was still shaken from the wreck and was having trouble making sense of what happened. “It’s really hard. I’m not sure I understand it too much.”

She said she was most disturbed by the fact that the drag racers didn’t stop. “I don’t want to say I hate them,” she said. “But I want them to get caught.”

Carrie Young, a spokeswoman for the California Highway Patrol, said the accident occurred about 7:40 p.m. as the drivers of two vehicles were racing each other in the southbound lanes just south of Alton Parkway, where construction narrows the freeway to three lanes.

The driver in the slow lane tried to switch lanes to keep pace with his competitor in the fast lane, Young said. In switching lanes, he collided with the Bronco in the middle lane. The impact was minor but the Bronco driver swerved to the left to avoid the impact.

Young said the Bronco’s driver tried to correct the swerving by steering to the right, but this caused the vehicle to overturn onto its left side and then to flip at least three more times. The three rear passengers were ejected.

Baughn was thrown from the van and died at the scene, Young said. Twohy died in the back seat as firefighters tried to cut her out, she said.

Besides Barnes and Siedentop, who sustained minor injuries, two other passengers were hurt. Paul Janicki, 21, and Daniel McDonald, 21, both of Placentia, were in serious but stable condition Sunday at Mission Hospital Regional Medical Center in Mission Viejo.

Both drivers of the speeding vehicles failed to stop, according to Young.

She described the vehicle that hit the Bronco as possibly a late-1970s or early-1980s dark blue Mercury Capri or a Chevrolet Chevette hatchback. The vehicle racing with that car was a black 1994 Honda Civic or Del Sol, witnesses told police.

Witnesses said the driver of the car that struck the Bronco was a Latino male in his 20s with shoulder-length hair. Young said anyone with information about the accident should call the Highway Patrol at (714) 547-8311.