Monterrey prison
Relatives of inmates gather outside the Topo Chico prison in Monterrey after deadly brawl claimed some 49 lives.Julio Cesar Aguilar/AFP

Officials investigating the Mexican prison where 49 inmates were killed in a brawl discovered a corrupt, out-of-kilter system run on bribes from drug kingpins that resulted in "luxury cells" that included aquariums, air conditioners, portable saunas, king-sized beds and flat-screen TVS. Yet the great masses of rank-and-file inmates were forced to pay steep prices to obtain barely acceptable water and food because of the bad quality of the meals provided by the prison.

The warden and superintendent of the Topo Chico prison in the northern city of Monterrey have been arrested and charged with drug trafficking and failure to enforce security measures. At least one guard faces charges of homicide in the shooting death of one of the inmates during the melee on 11 February.

Terrified relatives clustered outside the prison to await news of loved ones during and shortly after the bloody battle. "There is a riot. They want to kill us all. Come ask for me," one woman said her son told her.

Some of the inmates are inside for minor offences and some are awaiting trial in the prison many officials viewed as a powder keg. Yet drug lords were treated like sultans in the prison.

Zetas drug cartel leader Ivan Hernandez Cantu had a king-sized bed in his cell, a huge flat-screen television and a luxury bath, according to the state prosecutor's office in Nuevo Leon. "At the time of the attack, a lady was with him," chief prosecutor Roberto Flores told Agence France Presse.

Those with money enjoyed special food stands, convenience stores and even a bar that were operated by inmates, officials said. The deadly brawl erupted following a battle for control of the prison between Hernandez and rival Zetas leader Juan Pedro Zaldivar Farias, said authorities.

Most of the victims were stabbed or beaten to death with sticks by other inmates during the melee. Others died in a fire that erupted during the brawl.

Authorities found scores of makeshift knives, hammers and drugs in the prison the day after the massacre. They also found hundreds of figures of Santa Muerte, a "death saint" worshiped by criminals.

Local police have taken control of the prison to "put an end to the self-government that leaders of organised crime exerted with the complicity of some authorities," said a statement from the state prosecutor.

All the luxuries have been confiscated, officials said. "All the privileges are over," declared state public safety chief Cuauhtemoc Antunez. The prison had 3,800 inmates at the time of the riot, 35% over capacity. Some 233 inmates, including the two Zetas leaders, were transferred to other prisons after the brawl.