Mexico City ? Hundreds of police stormed a capital-area neighborhood Wednesday night, breaking down doors in a hunt for the leaders of a vigilante mob that burned two police officers to death.The massive incursion came a day after news cameras recorded the fiery deaths: A young man, his face bloody and swollen, struggles to tell a television reporter that he is an undercover federal agent, then a mob pours gasoline on him and a fellow officer and sets them ablaze.

The horrific footage, carried by all major television networks, put a spotlight on growing vigilante justice in Mexico, where police are viewed as inept at best and corrupt at worst and where many people say they must take security into their own hands as crime soars.

Around dusk Wednesday, police and federal agents aboard a convoy of government vehicles sped into San Juan Ixtayopan, sealing off streets and mounting a house-to-house search for the mob leaders.

Officials said at least 20 people were arrested in the 2 1/2-hour sweep. Three were directly involved in organizing the mob killings, and at least one was accused of sparking the blaze, officials said.

The officers’ deaths came amid rumors that children had been kidnapped from an elementary school in San Juan Ixtayopan, a neighborhood of 35,000 people on Mexico City’s southern outskirts. When people saw three men taking photos Tuesday and staking out the school, they took action.

Neighbors poured into the streets, where they cornered and then beat the men. Onlookers cheered and shouted obscenities.

Reporters arrived, and the assailants pushed the victims before TV cameras so they could be interviewed. Barely conscious and struggling to talk, they nodded and gave one-word answers when asked if they were federal agents.

As television helicopters hovered overhead, police arrived. One agent was rescued. He was in critical condition Wednesday evening, authorities said.

The other two officers were soaked with gasoline and set ablaze, their charred bodies left in the street as dozens of people milled around.

The federal police director, Adm. Jose Luis Figueroa, said the three plainclothes agents were in the neighborhood to investigate drug dealing near the school.

There appeared to be little remorse in San Juan Ixtayopan. Before Wednesday night’s raid, people milled about in the central plaza, discussing the bloodshed.

Many people were reluctant to speak to reporters. Some denied being present during the beatings. Others said they cried through the night after failing to stop the assault.

But some residents complained police had ignored reports of the kidnappings and said they did not regret what had happened.

“If the police aren’t going to do anything, then the town has to take matters into their own hands,” said 15-year-old Maria Eva Labana, who said she witnessed some of the attack firsthand before she ran home to watch the rest on TV.

Figueroa said a heavy case load had kept authorities from concentrating on the purported kidnappings. Community leader Mario Rios said he had received no reports of kidnappings and knew nothing of children disappearing.