He said there was no information as of Friday that would link the military to the shooting, adding investigators here are working with authorities in Mexico.
Garcia pointed out Mexico uses its military to patrol the U.S./Mexico border.
According to The Associated Press, two Baja California newspapers have reported that the Mexican army was fired upon by smugglers in at least one or maybe two load vehicles trying to cross the border. The newspapers reported that could have sparked a gun battle.
According to initial reports Friday eight people were wounded in the shooting.
Garcia said Friday the actual number of wounded was six, with two in critical but stable condition in San Diego-area hospitals, two treated at El Centro Regional Medical Center and two at Pioneers Memorial Hospital in Brawley.
A nursing supervisor at Pioneers said the immigrants were not at the hospital as of Saturday, indicating they had been released. A supervisor for El Centro Regional said one immigrant remained in treatment but was stable. The second was thought to have been released.
All those shot were men, Garcia said.
The victims were driving in a 1980s model tan-color Chevrolet Suburban crammed with more than 20 undocumented immigrants. Depending on the agency interviewed, the number of immigrants reported to have been in the vehicle has varied between 21 and 23.
Among those in the vehicle, 17 were thought to be from El Salvador, one from Ecuador and the rest from Mexico. The immigrants included men, women and a girl thought to be 3 years old. Neither the women nor the child was injured in the shooting.
The shooting occurred around midnight Friday as the Suburban was being driven without its headlights illuminated on the Mexican side of the border west of Calexico in a remote area of the desert.
At one point, according to Garcia, another vehicle that reportedly was parked shined its headlights at the Suburban and it was about that time that the shooting started.
Garcia said he wasn't sure how many times the Suburban was fired upon. What he did say is that the vehicle from which the shots were thought to be fired chased the Suburban, which crossed the border into the Imperial Valley.
Once in the Valley more shots were fired, and about 75 yards north of the border the Suburban came to a stop. It had a punctured front tire, but Garcia said he wasn't sure if that was from the shooting or from the rough terrain.
Garcia credited Border Patrol agents, who saw two vehicles cross the border, for responding quickly to the scene.
"They probably scared off the suspects," Garcia said.
However, by the time Border Patrol agents arrived the second vehicle they had seen had disappeared, likely back into Mexico. Garcia said he couldn't say for certain whether the second vehicle the agents saw was the one from which the shots were fired.
Garcia and Border Patrol Agent Manuel Figueroa said it is likely at least some of the people, including the driver of the Suburban, fled back into Mexico when the vehicle they were in came to a stop.
Garcia said investigators had yet to determine a motive for the shooting.
Authorities have the Suburban, which has a bullet hole in the driver-side window and along the sides of the vehicle, impounded.
Garcia said he expects investigators to probe the vehicle on Monday looking for clues, including any drugs that might be hidden in the vehicle.
Of catching the gunmen, he said that is a difficult task.
"The suspects are like ghosts," he said.
Regarding the type of gun used, Garcia said that was still under investigation. He said it appears a high-caliber weapon was used, but based on witness reports it did not sound like a machine gun
"They didn't hear rapid fire," Garcia said.
>> Staff Writer Darren Simon can be reached at 337-4082.