Detectives working on the Claudia Lawrence case told Crimewatch new leads could be 'hugely significant'.
They are looking for two men and two vehicles. Police said one man had a rucksack, he walked up to a green door, possibly Claudia's. The woman at the door 'looked surprised' and let him in.
A forensic team has spent two months re-examining Claudia Lawrence's terraced home. Her mobile and rucksack have never been found. Her hair straighteners also appeared to be missing.
"From the review of all the evidence available, including the fact that Claudia's bed was made and it appears that she had eaten breakfast and brushed her teeth, it is our belief that she had left for work on the morning of Thursday 19 March 2009.
"What is unusual is that Claudia's GHD hair straighteners - model number 14.4.1B and purchased in May 2007 - were missing from her home.
"From our inquiries, it is doubtful that she would take them to work in her blue and grey Karrimor bag which has also never been found."
Claudia's sister, Ali Sims, told Crimewatch that the press portrayal at the time was "so unfair" and made her seem like a 'manhunter'.
"Yes, she was pretty, she had lots of admirers, it's just how a normal 35-year-old would lead their life," she said.
"We know that a lot of people came forward at the time, but there are still some people that we want to come forward.
"Imagine living with not knowing what has happened to a member of your family, day in day out, for five years, the wondering. We just need to know what's happened to her, we need to find her."
More top news
Paul Brand meets more parliamentary candidates in our last political programme before the General Election. Watch it here:
A look ahead at the forecast for the Tyne Tees region.
A report from the Royal Society for Public Health ranks Middlesbrough 2nd in its list of the towns with the least healthy high streets.