A group of people frogmarched a naked young man through the streets of a Bedfordshire town in what police have described as a "brutal attack".
The incident happened in Rothbury Court, Carrick Road and Hamsterly Close, Bedford, early on Sunday.
The man was forced to wear a sleep mask and assaulted by the group.
Det Con Darren Armitage said: "This was a particularly brutal attack on a vulnerable man by a group of young people who assaulted him."
He added: "They made him walk naked through the streets from Rothbury Court to Hamsterly Close where he was assaulted further."