The Montressor was a 29th century prison transport.
When the tunnel was reopened two months later and the emergency services sent in, all of the ships were deserted. This became known as the "Mystery of the Cerberus". In fact, the Arachnopods on the Montressor ate most of the occupants of the ships, and the rest were taken to the year 3012 by the Repulsion. (PROSE: Festival of Death)