Read the latest on this case -- in Spanish -- at CNNMexico.com. 
 
 (CNN) -- Police in Mexico City have detained three people in the mysterious disappearance of 12 people from a nightclub, the city's attorney general said. 
 
 And for the first time since the disappearance, Attorney General Rodolfo Rios confirmed there is evidence showing that the people who are missing had indeed been at the club. 
 
 The names of the detainees -- one woman and two waiters from the Heavens After bar -- were not released. Officials said they are looking at the link between the woman and the waiters, but did not say what charges, if any, they might face. 
 
 Before Tuesday's announcement, the relatives of the missing people -- one of them only 16 years old -- insisted that they had been kidnapped from the after-hours bar in Mexico City's Zona Rosa entertainment district. But police had said there was no proof that that the 12 had even been there. 
 
 "There is evidence that the majority of the youths arrived at Heaven in two vehicles, one private and a taxi, but it is unknown how they left," Rios said. 
 
 Still, he said, there is no evidence that an armed convoy snatched the group, as the families say. 
 
 The attorney general also upped the number of missing to 12 from 11, saying that another family had come forward. 
 
 The top prosecutor met with the families of the missing to give them an update. 
 
 "We are not interested in who took them, we are not interested in any of that, whether they will be punished, or not punished doesn't interest us," said Carlos Ruiz, the father of one of the missing. "Our interest is that they all return alive." 
 
 Not all of the 12 people said to be involved knew each other, but most of them hail from the Tepito neighborhood, a place known for its rough character. That alone has added spice to an already sensational story, leading to speculation that gangs could be involved. 
 
 The young people were taken from the Heavens After nightclub on Sunday, May 26, between 10 a.m. and noon, family members say. They were forced into a van and kidnapped, they claim. 
 
 A center for missing persons in Mexico will distribute photos and information about the missing young people across the country. 
 
 A mass kidnapping would be a significant development because even through the years of drug cartel violence, the capital was a relatively safe place. Recently, however, there is evidence that infighting between local criminal groups is on the rise. 
 
 More than 26,000 people have gone missing in Mexico over the past six years as violence surged and the country's government cracked down on drug cartels, according to Mexico's Interior Ministry. Authorities don't have data on how many of the disappearances were connected with organized crime. 
 
 READ: Mystery deepens around missing Mexican youths ||||| Image caption Relatives of the youngsters have put up posters where they disappeared 
 
 Police in Mexico have detained three people in connection with the disappearance on 26 May of a group of 12 revellers from a bar in Mexico City. 
 
 The youngsters' disappearance in broad daylight from a popular entertainment district in a central part of the capital has raised many questions. 
 
 Relatives say the police have turned a blind eye to the case because the missing come from a poor area. 
 
 Amnesty International says authorities are failing to prevent disappearances. 
 
 Inconclusive evidence 
 
 Police said they had arrested two waiters, who worked at the Heaven bar in the Zona Rosa district of Mexico City, and a woman, in connection with the 12 missing revellers. 
 
 Officers are still looking for the owner of the bar, who they say is now considered a fugitive, after searches of a number of premises he had listed as his addresses turned up nothing. 
 
 My husband is paying for his crimes, and my son has nothing to do with that. If they were after him they would have taken just him, and not the other 11 Leticia Ponce, Wife of crime boss Jorge Ortiz Reyes 
 
 Mexico City Attorney General Rodolfo Rios said investigators were still analysing video footage from surveillance cameras in the area to establish what exactly happened on the morning of 26 May. 
 
 Mr Rios said it showed members of the the group - seven men and five women - arriving at the bar, but not leaving it. 
 
 Their disappearance made headlines when their relatives blockaded a street in the Tepito district of Mexico City, demanding that police take action. 
 
 The relatives alleged that officers had done nothing after being informed that the group had gone missing. 
 
 Investigators said they had interviewed people who were in the area at the time of the disappearance, but said only one man had reported seeing anything suspicious. 
 
 According to the man's account, masked gunmen stormed into the Heaven bar at 10:00 on Sunday, seized the group of 12 youngsters and drove away with them in several vehicles. 
 
 Officers who tried to question the man further said he had provided a false name, telephone number and address. They have not been able to locate him since. 
 
 Investigators said they had not found any trace of a struggle inside the bar. 
 
 'Move Heaven and Earth' 
 
 Relatives of the missing have accused the authorities of not acting in a timely manner because most of the members of the group reside in Tepito, one of the poorest and most dangerous areas of Mexico City. 
 
 Three of the missing are related to Tepito crime bosses currently serving time in prison, which has led to speculation in the media that the group may have been kidnapped by a rival gang. 
 
 Image caption The families of the missing are demanding the police dedicate more resources to the search 
 
 Leticia Ponce said she had delayed telling her jailed husband, Jorge Ortiz Reyes, about the disappearance of their 16-year-old son, Jerzy, in order not to "add to his worries". 
 
 Mrs Ponce said that once she did inform Ortiz Reyes, known as The Tank, he had told her "to move Heaven and Earth to find my baby". 
 
 Ortiz Reyes' son-in-law is also among the missing, but Mrs Ponce said she did not think their disappearance was linked to her husband's criminal history. 
 
 "My husband is paying for his crimes, and my son has nothing to do with that. If they were after him they would have taken just him, and not the other 11," she explained. 
 
 While mass kidnappings are not unusual in Mexico, they tend to occur in states where cartels vie for control of drug-smuggling routes, and normally involve members of rival gangs. 
 
 A mass kidnapping in the centre of the capital during daylight hours would constitute a major escalation in the violence the city has experienced. 
 
 Official figures say 26,000 people have gone missing across Mexico since December 2006, when the army was deployed to fight crime gangs. 
 
 On Tuesday, Amnesty International said the Mexican government was not doing enough to investigate the disappearances of thousands of people. 
 
 "Disappearances in Mexico have become commonplace because federal and state authorities have tolerated and refused to clamp down on them," the human rights group said in a new report.
– A mysterious case persists in Mexico City, where a dozen young people seem to have simply vanished from a bar in broad daylight. Their parents say police haven't done enough since their children—the youngest of whom is 16—went missing early May 26, because they come from a poor neighborhood. Since then, the story has made headlines around the world, and police today arrested two waiters from the bar and another woman; they're still looking for the bar's owner, who is now considered a fugitive, reports the BBC. The parents insist the disappearance was a kidnapping. But investigators say there is no evidence of an abduction, and only one person on the scene claims to have seen anything—in his telling, masked gunmen stormed the bar and seized the group, but he has since disappeared, leaving behind a false name and contact info. To make things twistier, three of the missing young people are related to crime bosses currently in prison, fueling theories that a rival gang may be involved. And a CNN report makes things twistier still: Police say they've identified no fingerprints from any of the missing on the bottles or glasses found at the bar.