A young man had to be brought to hospital after he was struck over the head and had his mobile phone stolen while walking through O'Hanlon Park in Dundalk last Wednesday night.
The young man was with a friend when an unknown male thumped him from behind and took his phone.
The incident occurred at 11pm.
The assailant is described as wearing a black jacket with a hood and grey tracksuit bottoms.
Anyone with any information is asked to contact Dundalk Garda Station on 0429388400.