The incident happened at around 3.10pm on June 30 when a man in his 50s had a verbal disagreement with another man who began swearing at him.
This escalated into a physical altercation at the bottom of the Central Line escalators, where the man was put in a headlock and lost consciousness.
His attacker then fled the scene and boarded a Central Line train.
The man in the image may have information that could help police enquiries.
A spokesperson for the British Transport Police said: “Officers investigating after a man was strangled at Bank Underground station have released this image in connection.
“At around 3.10pm on Monday 30 June a man in his 50s was walking towards the Central Line escalators when another man walked past him and began swearing.
“A verbal disagreement began and escalated into a physical altercation at the bottom of the escalators.
“The man was placed into a headlock and lost consciousness before the other man fled the scene and boarded a Central Line train.
“Officers believe the man in the image may have information that could help their enquiries.
“Anyone who recognises the man or witnessed the incident should text officers on 61016 using the reference 391 of 30 June.
“Information can be given anonymously to Crimestoppers on 0800 555 111.”
