The last confirmed sighting of Mr Fenwick, was of him and Ms Melville getting off a bus at Fern Bay at around 1pm on the 30th of January.
Ms Melville told police she and Mr Fenwick had been at their friend Beccy Lane's home, until about 2:30am on January 31st and had walked to an oval in Stockton, where she left Mr Fenwick while she went to visit a near by house.
"I was only half an hour and left," she told AAP via Facebook.
"That's when I tried calling Steven only to find out his phone was off."
Mr Fenwick's mother, Debbie Fenwick, told the AAP the couple had only been dating for around two months when her son disappeared. "I have never met her and I didn't know of her," Ms Fenwick told AAP.
"Steven usually brings his girlfriends home and I'd met every single one of them."
"Samantha said she left him and he went off by himself (but) he would never leave a girl by themselves - ever."
Some of Mr Fenwick's clothes and possessions were found in the dunes of Stockton Beach.
Police say it is extremely unlikely he would go swimming there at night and alone, as his uncle drowned nearby.
"If people were with him he would go into the water at other beaches - but definitely not at Stockton Beach," Detective Sergeant Jeff Little told AAP.
NSW Police say they have received varying accounts of the evening from Ms Melville and have not ruled out Mr Fenwick's win on the pokies at Wests Nelson Bay club on January 30th as a potential factor in his disappearance.
A $500,000 reward for information which leads to an arrest in the suspected murder of Steven Fenwick has been announced by the NSW Police.
Steven Fenwick has been missing for 12 months
