Tenager Kirsty Bentley went out for a walk with her dog in Ashburton on New Years' Eve in in 1998, but never came home. Photo: supplied
Police investigating the killing of Ashburton teenager Kirsty Bentley are following 10 lines of inquiry.
A $100,000 reward for information relating to the 1998 homicide was offered in July, with police receiving more than 80 pieces of information from the public.
The 15-year-old had been out walking her dog in Ashburton on New Years' Eve 1998, and never came home.
The dog and her underwear were discovered the next day, but Bentley's body was not found for another 18 days - partially buried 60 kilometres away, near the Rakaia Gorge.
In a statement, detective inspector Greg Murton said about 10 leads had been prioritised for follow up.
"This information has now been collated and prioritised," Murton said.
"Of these, approximately 10 have been prioritised for follow up, with another 40-plus pieces of information requiring additional enquiries, and about 14 requiring no further action."
The reward will remain on offer for six months.
Police have indicated prosecution may be considered for any accomplices.
"Our team remains committed to identifying the person or persons responsible for Kirsty's death to account and finding answers for her family," Murton said.
"We continue to urge anyone with information to contact police."