CONTROVERSY STILL SURROUNDS COLOSIO KILLING.

Byline: Dana Calvo Associated Press 

Two years after the slaying of Mexican presidential candidate Luis Donaldo Colosio, one gunman is in prison and a second gunman suspect is on trial.

Despite that, mourners returned to this hillside slum Saturday not only to pay their respects on the second anniversary of Colosio's death but also to protest what they say is the government's effort to protect the real masterminds of the assassination.

"They know the truth," said Jesus Sanchez, 80. "They know everything, but they're not telling us anything."

Sanchez's small green house sits across the street from the memorial plaza for Colosio. The plaza is the place where Colosio - then the chosen successor of President Carlos Salinas de Gortari - arrived for a campaign rally March 23, 1994.

He was felled by a shot to the head. Another bullet struck him in the abdomen.

The motive for Colosio's murder remains murky. Conspiracy theories abound, as does conflict on everything from the number of gunmen to the different angles of the two bullets. In two years, three successive prosecutors have been appointed to the case.

Gunman Mario Aburto sits in prison, serving a 50-year sentence for the murder. He confessed in a written statement while in federal custody, two days after the shooting. In December, Aburto claimed he was tortured into signing the confession.

The trial of a second man, now under way, flies in the face of the original federal prosecutor's announcement that Aburto was the lone gunman.

A newspaper poll published Friday in Mexico City showed that 62 percent of Mexicans surveyed believe that Salinas wanted to change his mind about a successor and ordered the killing of Colosio.