Egypt has referred 22 policemen to trial over a prison break near the Suez Canal city of Ismailia.

Prosecutor Amro Sami issued his ruling Wednesday, nearly a month after six convicts escaped following clashes with guards that killed a policeman and a civilian.

The police face charges of negligence after investigators found that the inmates had smuggled weapons into the facility with the help of visitors.

Policemen rarely go on trial in Egypt. Nearly all of the 100 policemen charged with killing protesters during the 2011 uprising that toppled Hosni Mubarak were acquitted.