CHULA VISTA, Calif. — An oft-deported Mexican citizen drove drunk and caused a hit-and-run crash in San Ysidro that seriously injured a 6-year-old boy, a prosecutor alleged today, but a defense attorney told jurors that her client wasn’t behind the wheel at the time of the collision.

Constantino Banda, 39, is being tried at the Chula Vista courthouse on charges of hit-and-run causing serious injury, DUI causing injury, driving with a blood-alcohol content over .08 percent, vandalism, battery and driving without a license.

The defendant has been deported from the United States at least 15 times over the past 15 years, most recently on Jan. 18, according to federal immigration officials.

Deputy District Attorney Christopher Chandler said in his opening statement that Banda was behind the wheel when his truck blew through a stop sign at Camino de la Plaza and Dairy Mart Road and T-boned a Honda Accord carrying 6-year-old Lennox Lake and his parents as they returned home from a day at Disneyland about 11:20 p.m. on May 6.

“There was significant intrusion into the rear compartment of the passenger side of the vehicle. You can see the current airbag deployed where Lennox was seated in his child seat,” said Deputy District Attorney Christopher Chandler.

Chandler said Banda, his brother and a man who worked for the defendant, Jorge Adame Ariza, had been at a Chula Vista seafood restaurant/bar watching a boxing match before the crash.

Banda’s estranged wife and her friend were also at the eatery, and the defendant flattened the tires on the friend’s vehicle and another car before leaving, the prosecutor alleged. He also grabbed the friend of his estranged wife, and a bystander who intervened got into a fistfight with Banda, according to the prosecutor.

Adame drove away with Banda in the passenger seat, but Adame told police that Banda was behind the wheel when the accident occurred about a half-hour later, Chandler told the jury.

When Border Patrol agents found Banda’s truck parked on a street not far from the crash scene, he was in the driver’s seat. The defendant failed a number of field sobriety tests and his blood-alcohol content was measured at more than .15 percent, the prosecutor said.

Investigators looked at Banda’s body and found seat belt markings that indicated he had been driving the truck at the time of the collision, according to the prosecutor.

But Deputy Public Defender Juliana Humphrey said police made up their mind quickly that Banda was the driver who plowed into the Lake family.

“I moved the car to the curb but I wasn’t driving. He tried to tell his story about the evening, about being in a fight and about being hurt and about his worker driving him. Nobody wanted to hear it,” said Defense Attorney Juliana Humphrey.  “Law enforcement presumed Banda was guilty because of where he sat. From where you sit, you have the opportunity to look at more. You have the opportunity to gauge the credibility of everything that was not available then.”

Later, evidence was developed that showed Adame was the driver of the truck at the time of the accident, Humphrey told the jury.

“It was he (Adame) who did not stop. It was he (Adame) who did not render aid,” the defense attorney said.

Humphrey admitted that Banda popped the tires in the restaurant parking lot so his wife would have to go home with him.

The attorney alleged that Adame — who was given immunity to testify — lied and gave inconsistent statements to police.

Humphrey said Adame — who had only been in the United States for 14 months — got confused and first headed south before turning around near the border and driving north before getting into the accident with the Lake family.

“Knowing that he’s lying and you know the struggles we are having because they’re not, Mr. Banda or his wife are not cooperating with insurance, the investigation or anything it’s getting harder to go in all the time and see him,” said Lennox’s mother, Ingrid Lake.

Banda faces seven years and eight months in prison if convicted.