By Duncan Kennedy
BBC News, Mexico City
About 500 people were in the nightclub when police raided it, officials said
The authorities in Mexico City have fired 17 police officers after a nightclub raid caused a stampede that killed 12 people.
The man in charge of the raid could now face homicide charges.
He allegedly told his officers not to let anyone else out of the club, because police vans were full.
Nine young club-goers, including a 13-year-old girl, were killed in the crush. Three police officers also died and 20 other people were injured.
Friends and family have targeted the police in Mexico City.
It all happened during a police raid on the News Divine club to investigate claims of underage drinking and drug sales.
Police blamed the club owner for the tragedy, saying he had announced that officers were there to arrest everybody.
But now a video released by the city's public security department appears to show police blocking one of the main exits. They are shown forming a barrier on the stairway that leads to the exit.
A number of young people can be seen screaming and beating on the ceiling of the stairway, trying to get out.
Police force civilian employees who helped organise the raid have already been suspended.
The club's owner has been charged with selling alcohol to minors.