Police say that sometime between 2.30 am 3 am an 18 year old female was walking along William Street towards Brownlow Terrace in Lurgan and she was aware that a man was walking behind her.
The female stopped at the junction of Ulster Street to remove her shoes and this male then touched her inappropriately before making off.
This male is described as being in his late 40s, 5ft8 tall, overweight with a bald head.
Police are appealing to anyone who noticed either the female or male walking in this area or who witnessed this incident to contact them in Lurgan on the 101 non-emergency number quoting ref. 1111030814.