Riley Strain, a student at the University of Missouri, was last seen in a bar in Nashville, where he was visiting with his fraternity house, just before 10pm on 8 March.

On Monday, police released footage showing the 22-year-old briefly speaking with an officer who was responding to a stolen vehicle incident on Gay Street - minutes before Mr Strain was last seen.

The video shows the officer asking Mr Strain how he is doing, to which he replies: "I'm good, how are you?"

The student "did not appear distressed", police said - and continued to briskly walk past the officer after the interaction at about 9.52pm.

No further footage of Mr Strain walking on Gay Street has been obtained after the brief conversation.

Police are continuing to search for the missing student, focusing on the embankment between Gay Street and the Cumberland River, where Mr Strain's bank card was found on Sunday.

The force said there is "no evidence of foul play".

Mr Strain's mother Michelle Whiteid and his stepfather Chris travelled to Nashville after learning of his disappearance.

Mr Whiteid told Sky News' US partner network NBC that his stepson had gone on to two more bars the same night he disappeared, before being kicked out of a third.

He said Mr Strain and other members of his fraternity, Delta Chi, were separated after being asked to leave Luke's 32 Bridge Food + Drink - and had last heard from his stepson at about 7.30pm on FaceTime.

Read more US news:
Donald Trump's assets under threat
US reaction to royal story is 'extraordinary'
Rust armourer calls for new trial after conviction

A separate video released by police on 12 March shows Mr Strain, wearing a half beige and half black shirt, crossing the road onto Gay Street with a group of people.

The student appeared to briefly stumble when reaching the curb.

"I've done a fair amount of drinking in my life, and I still question whether it was alcohol or something else," Mr Whiteid told NBC, referring to how Mr Strain appeared to have lost control of his balance.

He said since Mr Strain was reported missing, he has received multiple messages from people who claimed they were drugged while visiting bars in Nashville.

"I want Riley to know: we're actively looking for you, son," Mr Whiteid said. "We're going to bring you home."