A 50m long tunnel, 1m wide, with an overburden of 1.7m and equipped with lighting, made international news last month after it was used by 84 Brazilian prisoners to escape from jail.
Constructed using spades made from material destroyed in a prison riot four months previously, the tunnel’s alignment ran under two buildings and the boundary wall. It is not known if settlement was properly monitored.
Once free, the inmates fled in taxis that were booked using a mobile phone.