At least 75 inmates, many of them members of a notorious Brazilian gang, escaped from a Paraguayan prison in a border town on Sunday, according to authorities who said they immediately fired the prison's director.
Officials said they discovered a tunnel and found cells filled with as many as 200 bags of earth.
"It's not possible that nobody saw anything in all this time," Justice Minister Cecilia Prez told the Telefuturo station.
"This isn't the work of one day or one night."