He said the man and his girlfriend were fishing at Quinns Rocks beach about 6.15pm on Sunday, March 31. when he noticed a male spraying graffiti on a nearby wall.
‘He immediately grabbed his phone from his car and took some photographs of him,’ Constable Webster said.
‘The vandal, who was in company with three other males, took offence to being caught red-handed and assaulted him.
‘The victim was punched several times to his face, leaving him with a bloodied, swollen and bruised nose.’
Police have released an image of a man they want to speak to.
He was described as being olive-skinned, 183cm tall, of medium build with dark balding hair and blue eyes.
Anyone with information can make a report online or call Crime Stoppers on 1800 333 000, quoting reference number 6523.