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 man dubbed Britain's meanest thief was caught on CCTV walking calmly to a bar and swiping a collection box - for a cancer charity.
A 5p charge for single-use supermarket bags in England will cost taxpayers £1.5 billion over the next decade, a pressure group has claimed.
A record number of runners descend on Kielder in Northumberland for Britain's most beautiful marathon and half marathon.