Twenty-five police officers in Brazil have been given life sentences for their parts in the suppression of a riot in Carandiru jail, Sao Paolo, that left 111 prisoners dead.

The officers were each sentenced to 624 years for the deaths of 52 inmates in the 1992 riot.

Separate trials are taking place over the deaths on each of the four floors of Carandiru. In April, 23 officers were given life sentences in the first phase of the trial, with the whole process expected to conclude in January 2014.

When the riot broke out, Carandiru was one of Brazil's largest prisons, with about 10,000 inmates, more than double its 4,000 capacity. After an argument broke out between two prisoners, rival prison gangs and factions got involved before riot police were sent in.

Inmates say the unrest was brutally suppressed, and that officers shot them indiscriminately.

The officers' lawyer, Ieda Ribeiro de Souza, argued that his clients were performing their duty and feared for their lives, as many of the prisoners were armed.

In 2001, Col Ubiratan Guimaraes, who led the police operation to regain control of Carandiru, was convicted of using excessive force and sentenced to 632 years in jail. But he was acquitted on appeal in 2006.

He was found shot dead in his Sao Paolo apartment later that year.

There has been public outrage at the length of time it has taken to bring the officers to trial.

In 2002 Carandiru was closed and later demolished, after inmates in 27 jails across Sao Paolo state rioted, taking thousands of visitors hostage.