Rather than seek to repair a travesty of justice, however, the judge kept both men in prison.

"She said, 'I'm sorry but the legal process must continue,' " said Campos, Granada's wife.

It would take another five months for Aldo Christopher Granada Rivera to regain his freedom, only to endure lasting damage to his reputation and psyche.

After seeing his photo splashed on television under the words "Most Wanted," neighbors began to suspect that the entire Granada family was up to no good.

"We've been stigmatized," Granada said. "We are branded as a family of murderers and kidnappers."

Gonzalez Placencia, the capital ombudsman, said his office had identified 21 cases of people put through public "perp walks" or portrayed as criminals by law enforcement officials, only to be freed for lack of evidence.

"What's bad is that these 'perp walks' create a public perception. The victims can't defend themselves," he said.

In cases where people are arrested by mistake, Gonzalez Placencia wants the state to publicize their release with the same vigor it uses to announce their arrests, and to offer compensation.

Mexico's runaway violence — and public concern about safety — is the underlying reason for police enthusiasm at showing off alleged criminals and demonstrating headway against crime. Most citizens hold police and prosecutors in low regard.

A report issued this week by a public policy center, Mexico Evalua, found that only one in 10 Mexicans have much confidence in law enforcement.

The report says 80 percent of Mexican crimes go unsolved, including murders.

A blend of factors has led to the high-profile televised exhibition of alleged criminals, experts say, including news outlets eager for higher ratings, a public anxious for any improvement in security and a desire by all levels of government to show improvements in their battle against crime by capturing wanted criminals.

"There isn't a sense of, 'We need to prove that this person is guilty.' It's just a presumption of guilt," said Eric L. Olson, a senior associate at the Mexico Institute of the Woodrow Wilson International Center for Scholars, a Washington research institution.

Lawmakers addressed the issue of due process for detainees with a 2008 constitutional revision that established rights such as the presumption of innocence. But they've never enacted a criminal procedures code to put that presumption of innocence into day-to-day law.

The ambiguity, Olson said, is also apparent in public attitudes.

"On the one hand, people acknowledge that the system is unjust. On the other hand, they want quick and decisive justice against criminals, specifically against those behind the escalating violence in the country," he said.

Television viewers tend to overlook the bruises on the faces of detainees, apparent signs of torture and coercion, or the scripted confessions they offer.

The tendency of police to stage arrests can backfire. The 2005 arrest of a Frenchwoman, Florence Cassez, has strained Mexico's relations with France. A day after Cassez's arrest, police staged a re-enactment and invited journalists from Televisa and TV Azteca to air it live. The journalists, who weren't told that the arrest had taken place the day before, thought they were broadcasting the event.