Stolen Mercedes Slams Car; Boy Gravely Hurt : Accident: Driver of speeding vehicle leaves scene after broadsiding a mother and two children. A suspect is later arrested after Irvine neighborhood is searched.

A 7-year-old boy was critically injured Monday when a man who had sped through three red lights in a stolen Mercedes broadsided the child’s mother’s car, police said.

The boy, Trent McGee of Irvine, was in extremely critical condition on a ventilator at Western Medical Center-Santa Ana, Police Lt. Sam Allevato said.

Following a six-hour, door-to-door search, police arrested John Eric Phelps, 31, of Dana Point on suspicion of felony hit-and-run, evading arrest, grand theft auto, reckless driving and other charges, Allevato said.

Phelps was held without bail because he is on parole, police said. They would not say what he had been convicted of.

The Mercedes was going about 100 m.p.h. when it attracted the attention of an off-duty motorcycle officer from Laguna Beach, who was getting on the Santa Ana Freeway from Laguna Canyon Road, according to Laguna Beach Police Chief Neal J. Purcell Jr. The officer, whom Purcell did not identify, was en route to repair his broken radio.

“The Mercedes was passing cars like they were standing still,” Purcell said.

Normally, the chief said, his officers do not involve themselves in traffic offenses outside their jurisdiction unless it is serious.

The motorcycle officer, who was in uniform and riding his police motorcycle, put on his red lights and began catching up with the car.

When it appeared the driver of the Mercedes did not notice him, Purcell said, the motor officer “turned on his siren to get his attention.”

The driver turned to look at the motorcycle and, within several minutes, exited the freeway at Jeffrey Road. Purcell said the Mercedes began to slow, then ran red lights at the bottom of the off-ramp and again at the intersection of Jeffrey and Walnut Avenue.

At that point, Purcell said, the officer decided to stop the chase but continued to follow the Mercedes with lights flashing because the officer was in unfamiliar territory and unable to use his radio.

“He made the decision not to pursue the car any farther,” Purcell said, and he did not see the accident at Jeffrey and Irvine Center Drive about an eighth of a mile ahead of him.

Cheryl McGee, 40, was driving a Peugeot station wagon with her 10-year-old daughter and son Trent through the intersection at about 9 a.m.

The Mercedes pushed the Peugeot against a median divider.

Neither the mother nor daughter was injured, but Trent suffered serious head injuries.

Phelps ran, and the motorcycle officer chased him, but lost him in a residential area, investigators said.

Irvine police cordoned off the area and began a daylong search. About 3 p.m., a home alarm went off at an unoccupied house on Lorraine Way, and Phelps was spotted riding from the house on a bicycle, Allevato said. After a brief chase, he was arrested, Allevato said.

The 450 Mercedes, a two-door convertible, had been reported stolen Sunday night following a break-in at Dana Point Foreign Car Service.