It happened in Dunfermline earlier this month.
The early morning incident saw a 25-year-old man suffer serious, but not life-threatening, injuries, and a woman, also 25, had her handbag stolen.
The attack happened in the Guildhall Street area between 4:30am and 5:30am on Saturday, April 2.
The man police are hunting ran down the High Street in the direction of Pittencrief Park.
Detectives described him as white, in his early 20s, around 5ft 8, slim build, with short dark hair and clean shaven.
He was wearing dark clothing and spoke with a local accent.
They have appealed for any witnesses to come forward.
Detective Constable Heather Cooper, from Dunfermline CID, said: “We’re appealing for anyone who was in the Guildhall Street or High Street areas of Dunfermline around the time of the attack and witnessed anything suspicious to please come forward.
“Any information could prove useful to our investigation.”Call police on 101, quoting incident 1475 of 2 April or Crimestoppers on 0800 555 111 if you wish to remain anonymous.”