The detective leading the hunt for university chef Claudia Lawrence has revealed a motorist saw a couple involved in a roadside argument after the missing 35-year-old was last seen alive and well.
Detective Superintendent Ray Galloway told reporters in York it was a "significant" line of inquiry with Miss Lawrence now missing for more than four weeks.
Miss Lawrence was last seen on March 18 after she finished work at the University of York's Goodricke College and has not been in contact with anybody since around 8.30pm that day.
Police fear she may have come to harm after meeting someone she knows.
Mr Galloway said the motorist was driving towards the university along University Road when he came across the couple at 6.10am on March 19.
He said the car, which he does not have a description of, was parked on the left-hand side with a passenger door open. The witness told police he saw a couple on the other side of the carriageway involved in some form of verbal argument.
Mr Galloway told reporters in York: "The man and woman appeared to be in some form of altercation. We think it was a verbal altercation.
"He drives past and, as he looks in his wing mirror, his rear view mirror, he actually believes the man is stood above the woman i.e. as if he is on some form of banking. It's a significant line of inquiry which we wish to pursue."
The detective said it was possible it wasn't Claudia and he had no description of the couple involved. However, he said it was a "key moment" for the inquiry team as it was the morning Miss Lawrence was due to turn up for work at the university.
Mr Galloway also revealed that, on March 10 or 13, a woman motorist passing by Miss Lawrence's home on Heworth Road in slow moving traffic saw two men outside the chef's front door. One was described as an Asian male, while police have no description of the other man.
