A group of people could be witnesses to an altercation between a man and a woman, police believe.
At 11.30pm on October 5, there was an altercation between the man and a woman on Millennium Bridge.
Officers have been told that a group of two or three people came across the disturbance and went over to the woman, causing the man to run from the scene.
Officers are very keen to speak to them as they may have information that is vital to the investigation.
PC Ste Brown who is investigating said: “I would appeal directly to this group of people, if you see this appeal; please get in touch with us by calling 101 and quoting log number LC-20131005-1945.
“Similarly, if anyone has any other information that they think might help, they should also call 101 and quote that log number.”
People with information can also contact the independent charity Crimestoppers anonymously on 0800 555 111 or on-line at Crimestoppers-uk.org.
No personal details are taken, information is not traced or recorded and you will not go to court.