Hawke's Bay police are investigating the second assault on a young male in Napier in as many days after a teenager walking through suburban Tamatea was punched from behind without warning.
It came a day after a 12-year-old boy visiting from Tauranga was assaulted near a riverbank cycleway in Taradale by a man who had been cycling by.
The man took exception to the boy calling out a greeting to him.
The latest incident happened yesterday about 5.45pm as the 17-year old was walking along York Avenue towards Wharerangi Road.
A police spokesman said the teenager had headphones on listening to music and had no indication his attacker was approaching.
"He was suddenly and inexplicably punched to the head from behind."
The punch caused the teenager to fall to the ground, and after he got up he was confronted by a shirtless youth who was shouting obscenities at him.
He ran to his nearby home address and called police.
When speaking to police the victim noticed a group of five other young men nearby, but could not say if they had any association with his attacker.
Police now want to speak with those young men.
The victim said he did not recognise his attacker.
"He received a very sore head, scratches and a cut lip and is obviously very shaken by the attack," police said.
The offender was described as about 17, with brown skin and medium length hair - and stood out as he was shirtless.
Police said they were concerned at the "random and cowardly" nature of the attack.
Anyone who may have witnessed the incident or may know who the offender is can contact Hawke's Bay police on 06 837 0100 or anonymously on Crime Stoppers on 0800 555 111.
Police are still seeking the man, aged in his 40s or 50s, who carried out the assault on the 12-year-old.