Assassin Kills Mexican Ruling Party’s Presidential Candidate : Violence: Gunman in Tijuana reportedly tells police, ‘I saved Mexico.’ Front-runner’s death stuns nation and disrupts election plans.

Luis Donaldo Colosio, widely expected to be Mexico’s next president, was assassinated Wednesday in this border city--a killing that stunned the nation and cast a cloud over the future of its scheduled August national elections.

Colosio, 44, was pronounced dead of gunshot wounds shortly after 8 p.m., said Lievano Sainz, spokesman for the governing Institutional Revolutionary Party, known as the PRI, which had chosen Colosio as its presidential candidate in November.

“It is with great grief that I announce that, despite the efforts of doctors, Luis Donaldo Colosio . . . has died,” Sainz told a somber crowd of journalists and onlookers gathered in the smoke-filled lobby of Tijuana’s General Hospital, where Colosio had undergone emergency surgery.

Cries of disbelief emerged from the disconsolate crowd, guarded by black-uniformed Tijuana police and plainclothes state and federal police. “Murder!” and “Assassin!” shouted some of those who jammed the lobby and steps of the hospital.

Colosio was shot twice--once in the head and once in the abdomen--shortly after 5 p.m. in a Tijuana neighborhood not far from the city airport.

A suspect, identified by authorities as Mario Aburto Martinez, 23, was in the custody of Federal Judicial Police. He reportedly told police who interrogated him, “I saved Mexico!”

Also detained was Vicente Mayoral Valenzuela, 47. Authorities initially were unclear whether he was a witness or a suspect. But they said late Wednesday that he was a former head of the homicide division of the Baja California State Judicial Police in Tijuana and was being held as a witness.

Officials offered no immediate word about the motive for the assassination.

Colosio’s death shocked this nation, which prides itself on its political stability, and disrupted preparations for the Aug. 21 national elections.

Because no ruling party presidential candidate has died since the PRI was founded more than six decades ago, it was unclear how a successor will be named. But the process probably will involve the party hierarchy and federal elections officials, experts said.

That issue, however, seemed a distant concern Wednesday evening, when an air of national mourning seemed to grip Mexicans, who stayed glued to their television sets and radios awaiting word on Colosio’s fate.

He was shot after an hourlong campaign appearance in the poor neighborhood of Lomas Taurinas, a gritty community of unpaved roads and makeshift housing northeast of downtown. Wednesday was the first of a scheduled two-day campaign appearance in Baja California.

Colosio, dressed casually in a brown Windbreaker and open-neck blue sport shirt, spoke for about an hour. As he had in recent appearances, he stressed the importance of development in poor neighborhoods. “We are going to bring the power of the citizenry to the presidency of Mexico,” Colosio told residents.

During his address, Colosio made a point of predicting victory for the ruling party in the state of Baja California, which is controlled by the rival National Action Party. “Viva Baja!” Colosio said at the end of his address.

Upon completing the speech, witnesses said, Colosio walked down a sloping dirt road, shaking hands with residents, as he headed back to his motorcade. He was shot at 5:08 p.m.

“I was looking down when I heard a shot,” said Maria Vidal, a supporter who was walking with Colosio at the scene. “I looked up and saw the gun right in front of me. Then I saw him fall to the ground. Blood was coming out of his head.”

After the shooting, what one witness called an “avalanche of humanity” descended on the confusing scene. Loud music blared as the candidate walked down the road, so many were initially unaware that Colosio had been shot.

But the furious Tijuana crowd then surged around at least one of Colosio’s apparent assailants, beating him savagely. Television broadcasts from the chaotic scene showed the suspect as a muscular man in his 20s. He appeared bloody and disheveled.

Meantime, Colosio, critically wounded, was put into a Ram Charger truck and rushed away. He was later transferred to an ambulance and taken to Tijuana’s General Hospital, where hundreds of people gathered. Some offered to donate the rare blood type that Colosio was said to need.

Physicians at one point hoped to transport Colosio to nearby UC San Diego Medical Center, which could offer state-of-the-art trauma care. A helicopter was even dispatched for him around 7:30 p.m., but he was judged to be in too delicate a condition to be moved.

Dr. Rosalinda Guerra Moya, the Tijuana hospital’s director, said a team of eight physicians sought to save Colosio. Among those attending him was Dr. Patricia Aubanel, who runs a clinic in Tijuana and practices at the prestigious Scripps Clinic in San Diego. Aubanel was the primary physician for Mother Teresa of Calcutta when the 83-year-old Roman Catholic missionary and Nobel Prize winner was treated in San Diego for a heart ailment and pneumonia in 1992.

But physicians said later that Colosio’s head wound had been too severe.

Throughout Mexico, there were denunciations of Colosio’s murder. Mexican President Carlos Salinas de Gortari--who ordered the attorney general to go to Tijuana to investigate the killing--called Colosio’s assassination “a vile act . . . that hurts us deeply.”

In San Cristobal de las Casas in the southern state of Chiapas, Manuel Camacho Solis, the government’s peace negotiator and a longtime political rival of Colosio’s, called the killing a “grave offense to his family and a great, grave offense to all Mexicans.”

As angry Mexicans gathered at the police station where the suspect was said to be held, others at the hospital complained about the poor security at Colosio’s campaign stop. By contrast, some said that security was much tighter during a recent visit to Tijuana by Diego Fernandez de Cevallos, presidential candidate of the National Action Party.

“This is not the deranged act of a fanatic,” said Lourdes Felgueres, a human rights activist and ruling party supporter who was present at the rally. “This is the work of a hired killer. He knew exactly what he was doing. Justice must be done.”

For Mexico, and especially its ruling party, the assassination could not have come at a more difficult time. The government was badly embarrassed in January by the Indian uprising in Chiapas that left at least 145 people dead. Grass-roots rebels are now considering details of a tentative peace accord.

Colosio’s shooting also came one day after Camacho Solis announced that he would not run for president. The prospective candidacy of Camacho Solis had threatened to split the ruling party since January.

Tension about August’s elections has been mounting steadily since the Chiapas uprising. The rebels have called for broad national reforms leading toward a truer democracy; Salinas had pledged to push for a more democratic electoral process. Mexican lawmakers on Wednesday were considering a broad package of reforms.

In Washington, a State Department spokesman expressed shock, horror and sorrow over Colosio’s assassination.

Colosio was an amiable politician whose open manner contrasted with the stiff persona of many Mexican lawmakers. But Colosio had been controversial since he was named as the party’s candidate Nov. 28.

Salinas, exercising a traditional prerogative of Mexican presidents, personally chose Colosio--a native of the border state of Sonora and a longtime protege--as his likely successor, passing over Camacho Solis and other rivals.

But critics complained that Colosio adhered too closely to Salinas’ view on free trade and other neo-liberal economic policies of the PRI. Since the Chiapas rebellion, he had been distancing himself from Salinas’ economic plans, stressing the need to help the great numbers of poverty-stricken Mexicans.

Within the PRI, which has been synonymous with government here since its founding in 1929, Colosio was considerably more popular. Party stalwarts favored him for the presidency, confident that he would do nothing to erode the PRI’s longtime dominance. He was also much favored by this nation’s business community and international investors who, via the Mexican markets, expressed deep displeasure at the mere prospect that Camacho Solis might challenge Colosio.

Before being named PRI presidential candidate, Colosio headed Mexico’s vast Social Development secretariat, which included a multibillion-dollar anti-poverty initiative called Solidarity.

In the wake of the Chiapas rebellion, many criticized Solidarity as a program that did little to resolve the pressing problems of rural and urban poverty that still characterize Mexico.

Colosio also served as a PRI senator and chairman of the national party. An economist, he was a native of Magdalena de Kino, near the Arizona border, and did postgraduate work at the University of Pennsylvania and in Austria. His survivors include his wife, Diana Laura Riojas, an economist, and two children, Luis Donaldo, 7, and Mariana, 10.

Rotella reported from Tijuana and McDonnell from Los Angeles. Times staff writers Fernando Romero in Tijuana and Anthony Perry and Chris Kraul in San Diego and Juanita Darling in Mexico City, as well as Susan Drummet of The Times’ Mexico City Bureau, contributed to this report.