Nine inmates were killed, 14 were injured, and dozens escaped in a prison riot on Monday, national news media reported, in the latest example of Brazil’s continuing difficulties maintaining control over its notoriously violent penal system.

According to newspaper O Estado de São Paulo, 106 prisoners escaped the prison in the city of Goiânia, near the capital of Brasilia. Authorities recaptured 27 of the escapees, but the rest remained at large.

One of the nine killed in the mayhem was decapitated, news media reported, sparking memories of a prison riot that occurred one year ago today in the Amazon in which 56 people died, several of whom were decapitated and thrown over prison walls.

That riot, which was rooted in a long-standing gang rivalry, came at the beginning of a January marred by widespread prison violence, with 130 prisoners dying in the first 20 days of 2017.

Brazil’s prisons, which suffer endemic violence, are often severely overcrowded. Rights group call prison conditions medieval, with food scarce and cells often so packed inmates have no space to lie down.

In comments on Monday to newspaper Folha de São Paulo, the head of Brazil’s prison guard union, Jorimar Bastos, criticized the amount of resources allocated for oversight at the Goiânia prison, saying only five guards were assigned to watch over 900 prisoners, as reported by Reuters.