A 20-year-old man was left tied to railings after been beaten with hammers and baseball bats, police said.
Detectives in north Belfast are investigating the abduction and serious assault of the victim, who was taken from his home in the Shankhill area about midnight.
The PSNI said he was found at about 5am badly injured and tied to railings in the Sandy Row area.
"He is believed to have been beaten by unknown assailants by hammers and baseball bats," said a PSNI spokesman.
The victim is being treated in hospital for his injuries, which are not believed to be life threatening.
Anyone with information is urged to call CID at Antrim Road or Tennent Street.
Meanwhile, detectives are investigating an alleged serious sexual assault on a woman close to Queen's University.
Police in Ladas Drive are keen to speak with anyone who noticed any suspicious activity in the University Street or University Road area between 1.30am and 2.30am.