That involved reading witness statements and charting the movements of people and vehicles.
The Christchurch woman has repeatedly called for police to look into the case again, and continued her campaign by launching the Justice for Lisa Facebook page this week.
She met Taylor in prison in 2014, along with Blakie's father, Doug, and Taylor's lawyer, and he told the trio he saw a white Bedford van travelling towards Arthurs Pass after he dropped Blakie off.
He recognised three people inside as being from a gang, McMenamin said.
He did not initially tell police because he feared retribution, she said.
Two of the alleged occupants underwent DNA testing and were cleared, but a third did not, McMenamin said.
McMenamin has previously called for the man to be tested, before police told Doug Blakie this month they could not make the man give a sample, McMenamin said.
That had prompted her to start the Facebook page, which had more than 330 members three days after its launch.
"I'm hoping to get enough support and maybe next year we can get this case reinvestigated."
Doug Blakie told the Herald he supported the page, but did not want to comment further.
Detective Inspector Gregory Murton said in a statement police were satisfied with the result of the investigation.
"There is no evidence to suggest anyone else was involved in the abduction and murder of Lisa Blakie."