A Cleveland Police spokeswoman said the 22-year-old man arrested in connection with the incident has been released on bail.
The injured man remains in an induced coma in hospital, police confirmed.
Officers say they have been searching for all evidence from the scene. It is unclear whether they have found the missing penis.
More top news
A "vicious and scheming" killer murdered her boyfriend then tried to recruit a local butcher to help her dispose of his body has been jailed
A look ahead at the forecast for the Tyne Tees region.
Doctors across the North East are warning of a shortage in GP numbers