Soon after, the victim noticed his wallet was missing and spoke to the staff.
They reviewed security footage, which showed the man in the blue singlet removing the man's wallet from his pocket.
"We want to know who this bloke is and if he sees this I would suggest he get in touch with us as soon as possible," said Senior Constable Kevin Morgan.
"The person who took the photo in the library and gave it to us has done well to act so quickly and we're very grateful for their help"
Anyone who recognises the man is asked to phone 09 839 0600, private messaged the Waitemata Police Facebook page or contact Crimestoppers on 0800 555 111.