A man and woman were targeted by a group of hooded robbers as the victims stood on the balcony of a Luton property.
Police are appealing for witnesses after the attack at about 1am on Tuesday in Wigmore Lane.
The pair were on the balcony when they were approached by a group of men, all dressed in dark hooded tops, who accessed the balcony by climbing on a roof.
The woman managed to escape but the other was assaulted by the men before having his phone and wallet stolen.
Detective Constable Jabbar Khan, investigating, said: “These opportunist thugs assaulted and robbed an innocent man and we absolutely will not tolerate this type of behaviour. I’m appealing for anyone who may have witnessed suspicious activity in Wigmore Lane at around this time to get in touch.”
Anyone with information is asked to contact DC Khan on 101 or call Crimestoppers, anonymously, on 0800 555 111.