But the fact that the Cardinal was a close friend of President Carlos Salinas de Gortari and was known for his fearless pulpit sermons against the region's cocaine traffickers cast doubt on the official version of Monday's shooting. Cardinal Posadas, who was the Archbishop of Guadalajara and one of only two cardinals in Mexico, had been tipped to take over as Primate next year when Cardinal Ernesto Corripio Ahumada retires.
Reports that a Mexican air force uniform, an army document and baseball-style hats of Mexican anti-narcotics agents had been found near the scene added to the confusion and conspiracy theories. Cardinal Posadas went to the airport to meet the papal nuncio, Girolamo Prigione, and was to have organised the Pope's planned visit to Guadalajara in August.
The Cardinal's body, found in his car outside the terminal building, had been hit by at least 11 AK-47 automatic-rifle bullets, and a couple of dozen more bullets hit the car. His chauffeur was killed, and five others inside or outside the terminal. At least 20 cars were hit by bullets.
Witnesses said a gunbattle appeared to start in the arrival area of the airport then spilled outside, with scores of rounds of automatic rifle fire. One witness said the Cardinal opened his car door to get out when a gunman, already involved in the battle, opened fire on him.
First reports said the gunfight had been between police and drugs traffickers. Police later denied this and said rival groups of traffickers were involved. But many Mexicans, aware of the painful history of the Catholic Church in Mexico, described in Graham Greene's The Power and The Glory, doubted the 'coincidence' of the Cardinal's presence in the airport car park, particularly since he was hit so many times.
After more than a century of tension, President Salinas restored diplomatic relations with the Vatican last year. Until then, reflecting Greene's novel, priests hid their cassocks under normal clothes when on the street. Mr Salinas immediately flew to Guadalajara and, after hearing cries for 'justice' from the streets, observed a minute's silence in the cathedral before the Cardinal's coffin - the first visit to a Catholic church this century by a Mexican president.