Ms Furlong's skeleton was found buried in a sand dune at Port Waikato's Sunset Beach last month. A woman walking her dog saw a skull in the sand and alerted police, who later confirmed it was Ms Furlong.
Her family including her son Aidan, who was just five-months-old when she vanished, are planning a funeral for her.
Tonight Mr Benefield also made an appeal for a man whose name appeared in Ms Furlong's diary.
He said the man was recorded in the diary only as "Tommy". Ms Furlong may have planned to spend a night with him at about the time she went missing.
"If any of Jane's clients recall being with her on or after May 26 1993, they should contact us to enable us to get a clearer picture of her movements after that date. All information will be treated with confidentiality," Mr Benefield said.
"Our overriding objectives are to establish - as best we can - when, where, how and at whose hands Jane died and how she ended up buried at Port Waikato.
"It's likely more than one person was involved in her disappearance at some stage. Nineteen years have passed since she was snatched from her baby son and other family members and it's time now for those who know some or all of what happened to her to front up and tell Police."
Ms Furlong's mother Judith travelled to Sunset Beach on Monday to visit the place where her daughter was buried. She returned yesterday with Aidan.
"It was the first time her son had visited the scene since her skeleton was recovered and he too wants answers as to why his mother was killed and hidden in the sand for so long."