A second U.S. law enforcement official, who was monitoring internal communications after Sunday's shootout, also said the U.S. knew earlier that marines had killed Lazcano.
According to Mexican accounts, Lazcano was killed in a confrontation outside a baseball field about 1 p.m. Sunday in the town of Progreso, about 120 miles south of the Texas border. The navy said the marines were acting on a complaint from a local citizen about armed men in a truck and were coming up behind the vehicle when they took fire and grenades. The marines returned fire, killing the driver in the truck. Two others got out and ran. One got away, while the man later identified as Lazcano was felled by six bullets, two to the head, according to the autopsy.
Marines approached the bodies of Lazcano and his accomplice to confirm they were dead, then guarded the scene and called the Coahuila state attorney general's office, which had jurisdiction over an investigation into the killing, according to a Mexican military official who spoke on condition of anonymity because of the sensitivity of the information.
The official said marines called the state prosecutor's office twice, and waited for hours — an unusual amount of time — for investigators to arrive.
Vergara said in interviews this week that state officials didn't arrive until 7 p.m.
He said marines then accompanied the bodies to a funeral home in nearby Sabinas, though it's unclear what time. The marines left before midnight.
A Coahuila state forensics expert was called to the funeral home in Sabinas to process the body around 11 p.m. Sunday according to a state police official who was not authorized to speak to the press. The expert finished taking fingerprints and photographs about 12:15 a.m. Monday, and sent the information to the federal attorney general's office, the police official said.
A short-time later, gunmen forced the funeral home owner to take the body by hearse to an unknown location. The owner could not be reached for comment this week.
Stealing bodies of fallen accomplices has been described as part of the Zeta culture, in which soldiers don't leave their comrades behind.
Lazcano was believed to be a devout Catholic who wanted a proper burial. An elaborate mausoleum in his hometown in central Hidalgo state stands near a chapel that bears a bronze-colored plaque reading: "Donated by Heriberto Lazcano Lazcano, Lord, hear my prayer." The plaque also says the chapel was built in honor of Pope John Paul II.
The mausoleum has a 15-foot (5-meter) high chrome metal cross, stained-glass windows of figures such as red roses, the Virgin of Guadalupe and the sun's rays and clouds. A rectangular hole, possibly for a coffin, is near the windows, beneath a crucifix.
As of late last week, Mexican media images showed no change at the empty tomb and no acknowledgement that Lazcano had died — not even a single bouquet of flowers.
Olga R. Rodriguez in Progreso, Mexico and E. Eduardo Castillo in Mexico City contributed to this report.