A lawyer for Mexican poet Javier Sicilia says Sicilia's son and six friends were suffocated with tape and bandages in killings that sparked nationwide protests.
Attorney Julio Hernandez says the youths were beaten by bar employees near the city of Cuernavaca in March, then taken to a house and killed by other men.
The lawyer's Sunday statement says one of the youths was tortured. That victim accused bar employees of robbing his nephew days earlier, apparently sparking the attack on the seven young people.
Federal prosecutors, meanwhile, have announced that a judge formalized the arrests of 20 suspects detained in the case and they have been transferred to prisons.