They admitted last night that they had made little progress. Dr Meenaghan, 33, a lecturer at the Sir William Dunn School of Pathology at the university, was killed by a single shotgun round fired through a window as he made a cup of tea on Saturday afternoon.
His killer had sneaked down an alley alongside his modern brick house, smashed the window and pointed the shotgun at him at almost point-blank range. Dr Meenaghan. managed to make a 999 call as he collapsed with chest wounds but was unable to say anything before he died. Police broke into his home on the Blackbird Leys Estate, Oxford.
Neighbours said that Dr Meenaghan had recently increased security at his home, keeping his curtains drawn all day, switching to an ex-directory telephone number and locking the doors even when he was at home.
It had been suggested that the murder might be connected with his work. But this was not controversial and his £18,000-a-year salary was funded by research grants.
Contrary to some reports, he was not involved in research into DNA genetic fingerprinting, sometimes used by the police to identify murderers and rapists.
Moira Johnston, a spokeswoman for the University, said yesterday: "Dr Meenaghan's work focused on the study of the molecular biology of proteins involved in cell adhesion. This basic research addresses the issue of how cells communicate with each other and how this might go wrong in diseases. He was not working on anything to do with DNA."
Police have not ruled out the possibility that his death was a case of mistaken identity and that the murder may have been carried out by a contract killer.
There had also been speculation that Dr Meenaghan had a tangled love-life. He had separated from his wife some time ago and later another woman and her son moved into the house but left after a few weeks. Letters were found at his home indicating that hehad had other girlfriends.
Dr Meenaghan's present girlfriend arrived at the murder scene shortly after police had discovered his body.
A police officer said: "His girlfriend turned up at the house and was very shocked when she discovered what had happened. We believe she had telephoned him at home and at work as they had arranged to meet up that night and she had become concerned when she could not contact him."
Det Supt Jon Bound, the officer in charge of the inquiry, said: "We have been in touch with friends and girlfriends of Dr Meenaghan. But we still have no idea what the motive is for this death. "
"There was talk of domestic difficulties. He was married and there was a child but they are no longer in the area. He was a young man and cannot be criticised for having relationships with women. We are talking to friends and associates of Dr Meenaghan and we will be carrying out further searches of his house, garden and other areas."Reuse content