Mexicans Block Border Shooting Probe, Police Say : Investigation: Calexico police chief assails Mexicans for not allowing an interview with a youth wounded by Border Patrol. Mexican officials say the boy isn’t well enough.

The increasingly bitter binational controversy over the U.S. Border Patrol shooting of a 15-year-old Mexican boy intensified Friday when the police chief in Calexico accused Mexican lawmen of refusing to allow U.S. authorities to interview the victim and otherwise thwarting the investigation.

Mexican officials immediately denied the charges, contending that they were willing to cooperate with U.S. police, but that doctors were forbidding a police interview because of the youth’s slow recovery from bullet wounds.

Meanwhile, Calexico police disclosed that the Border Patrol agent who fired the shot alleges that he pulled the trigger as the youth, perched atop the border fence, had his arm cocked preparing to throw a rock at the agent during a rock barrage. That contradicts the version outlined by the youth and by Mexican officials.

The victim, Eduardo Garcia Zamores, who has been recuperating in a Mexicali hospital since the shooting, has denied ever having a rock or threatening the agent, according to Marco E. Lopez, the San Diego attorney who is representing the youth in a $9-million civil negligence claim filed this week against the Border Patrol. Four witnesses to the shooting, which occurred Nov. 18, have denied that the boy had a rock, according to Marco Antonio Tovar, the Mexican consul in Calexico.

The case has spawned outrage on both sides of the border, igniting huge protests in the Mexican border city of Mexicali that resulted Wednesday in a nine-hour shutdown of the busy international port and a halt to the flow of commerce and travelers.

Officials in Calexico, an Imperial County town of about 20,000 residents across the border from Mexicali, have voiced increasing concern about the incident’s effect on binational commerce--the city’s lifeline--and about the lack of details from the Border Patrol and Calexico police. City police are charged with investigating the incident, but the FBI has also begun a preliminary inquiry to determine if the youth’s civil rights were violated.

The Mexican Embassy in Washington has requested of the U.S. State Department that the case be resolved as soon as possible.

Meanwhile, the youth’s attorney has asked the Mexican government to seek the extradition of the agent to face criminal charges in Mexico, which both Mexican and U.S. authorities acknowledge is improbable. Mexican officials say they will await the outcome of U.S. inquiries.

Border Patrol officials and Calexico police have refused to identify the agent, who has been reassigned to light duties pending the outcome of the case.

Against that charged backdrop, Calexico Police Chief Leslie Ginn called a news conference Friday and lambasted his Mexican colleagues, contending that Mexican police had denied his investigators access to the youth and had withheld other vital evidence--including the 9-millimeter bullet that injured the youth, the teen-ager’s clothing and various police and ambulance reports. Calexico police have also been denied access to witnesses, Ginn said.

“They’re all turning their backs on us,� Ginn said of Mexican police. “Right now, we’re stopped in our investigation.�

Tovar, the Mexican consul in Calexico, said the boy’s condition had prevented a police interview. Mexican authorities are willing to cooperate, he said.

“We are confident of the system of justice in the United States,� Tovar said.

Chief Ginn said the agent involved in the shooting provided the following account:

Working alone, the agent was trying to detain a suspected illegal alien who was climbing the border fence. Garcia, the Mexicali youth who was shot, was positioned atop the 10-foot-high fence, facing the U.S. side, apparently watching as the agent tried to grab the other suspect. At the time, the agent told police, rocks were being thrown onto the U.S. side. The agent told police he fired in self-defense as Garcia was primed to hurl a rock at him.

Chief Ginn, a 29-year veteran of the San Diego Police Department before taking over as chief in Calexico 5 1/2 years ago, said his department is not hesitant to pursue such a sensitive case. “If they want justice,� Ginn said of his Mexican colleagues, “all they have to do is turn this over to us.�

Five years ago, Ginn noted, Calexico police investigated charges that Border Patrol agent Robert M. Ferrick had abducted a Mexican teen-ager and terrorized him for two days. The agent eventually pleaded guilty to a kidnaping charge and was sentenced to a six-month jail term.

In the more recent case, the agent’s contention that he fired his pistol as the youth was about to fling a rock was similar to a number of other controversial Border Patrol shootings in recent years, particularly the shooting in April, 1985 of Humberto Carrillo Estrada, a 12-year-old Tijuana youth who was shot through the fence as he stood in Mexican territory.

In that celebrated case, which also generated extensive cross-border protests, the agent, Edward D. Cole, also contended that he fired as the youth was about to throw a rock onto the U.S. side. The youth, who also survived, denied the charge. Several federal and state investigations found that the shooting was a justified act of self defense from a barrage of rocks.

However, a U.S. district judge in San Diego later ruled that the Border Patrol’s version of events was “incredible,� and the judge awarded the youth more than $500,000 in civil damages. Carrillo was also represented by Lopez.