Today, officers are appealing to a driver who may have spoken to Mr Lynch immediately after the 20-year-old was dropped off by a taxi in the early hours of Saturday 5 December.
Another witness believes he potentially saw Mr Lynch talking to a car driver. States police said that at first the witness thought this was the taxi that dropped Adrian off but having watched the media coverage he now believes his sighting was slightly later.
Police are appealing for this driver to come forward.
The sighting occurred around 12.20 am on the junction of Six Roads. The witness was parked at David Hicks and looked back down to the junction to see a car driver talking to a young man, believed to be Mr Lynch, who was leaning against the wall. The vehicle had the interior light on at the time.
As yet this driver has not come forward.
Mr Lynch, who was returning home from a Christmas party, was seen a number of times following this potential sighting however officers want to know what the conversation was and if this could give any more clues to his whereabouts or intentions.
Officers have also reiterated their appeal to homeowners to check their properties, or any property which would have been in the area at the time, such as boats and trailers, in case Mr Lynch has taken shelter and become trapped.
The latest development comes after experts from Humberside Police yesterday spent the day combing areas of water using high-tech sonar equipment in the hunt for the missing electrician.
The team of two police officers from Humberside Police worked alongside States police, Jersey Fire and Rescue Service and States divers to comb specific areas of water in the parishes of St Lawrence, St Mary and St John.
Searches were conducted in Handois Reservoir and further searches were due to continue today.
Any information should be reported to police on 612612.
