Riley Strain's mom reveals he text her saying a rum and coke he ordered from Nashville bar 'didn't taste good' before he was mysteriously found dead in river with no pants, wallet or boots

Riley Strain's mom has said her son text her to tell her his drink tasted strange hours before he disappeared.

Michelle Whiteid said Strain, 22, had ordered a rum and coke that 'didn't taste good' on the night he vanished, NewsNation reports.

The University of Missouri student's half naked body was plucked from the Cumberland River in Tennessee 14 days after he vanished, but an initial autopsy ruled out foul play.

Now his mom has shared her fears his drink may have contained something which could explain the circumstances.

'Maybe there was something in it that shouldn't have been,' Whiteid said, explaining that her son told her the drink 'tasted like barbecue'.

'I go, 'Well, that sounds awful,' Whiteid added. 'He said, 'Well, it sounds good, but it's not.''

 Luke's 32 Bridge Food + Drink where Strain was last seen alive in person said he was asked to leave after being served one alcoholic drink and two waters.

The Delta Chi fraternity member was in Tennessee on a group trip for their annual spring formal when he was kicked out of the bar around 10 p.m.

Surveillance video showed him falling as he walked the streets of Nashville before his disappearance on March 8.

Additional surveillance footage released by the Nashville police show him wobbling and appearing confused as he crossed a closed road near the water.

The next morning, his fraternity brothers tried to find Strain using his Snapchat location but were unsuccessful and called police to report him missing.

Whiteid said her son had been 'excited' for the trip, but her world came crashing down when she received a call from his friends informing him they could not find him.

'I said, 'What do you mean, he's with you? Why would I? What do you mean you can't find him?'' Whiteid recalled. '(The brother) goes, 'Well, he's not in the hotel, and we can't find him.''

His last cellphone location was recorded between Gay Street and James Robertson Parkway close to the bar where he was last seen.

A frantic search ensued and Strain was eventually found in the river without pants, shoes or his wallet.

An initial police autopsy found no signs of foul play, but no signs that he drowned. 

A second autopsy ordered by the family confirmed there was no water in his lungs, increasing fears that he was already dead when he entered the water. 

'One thing that threw the family for a loop was the coroner going on record stating about the lack of water in his lungs,' Strain's family friend told NewsNation. 

'Usually water in the lungs means that they were alive when they went into the water.'

Strain's stepfather Chris Whiteid says he wants to know what happened and that he will continue to look for answers.

'If he fell and truly fell in the water, and you can prove that to me, show me. I'll accept it,' he said to NewsNation. 

'But I can tell you from all the stuff that we've done as far as search and looking, taking pictures — I don't feel like it's really possible that happened. He may have fallen, but someone helped him in the water.'

The person who last spoke to Riley was said to have spoken to police earlier this month, with the family praising it as a 'huge' development. 

Family friend Chris Dingman, told NewsNation's Elizabeth Vargas Reports this week that the witness 'told the detective his account of the story of what happened to Riley.'

The video surveillance from a nearby detention center may hold the key to Riley's final moments.

Dingman said one of the videos from one of the cameras have been made public, but the others have not been available to the family.

'The detention center is just north of the last ping on Riley's phone. It was the only video released to the public, ' he said.

The family's worst fears have been further stoked after a renowned forensic expert came out to say he believed Strain's state of undress could indicate he was murdered.

'I would say somebody took them off,' Dr. Bill Bass, who founded the University of Tennessee's famed Body Farm, said of Strain's pants.

'If you do research on this, it would be very difficult because you've got to kill a person to do it, but it is difficult to get your pants off,' he explained to News Channel 5.

'It's difficult when you are alive to get your pants off.'

'It is unusual. Normally if you fall in the river, it's very difficult to get your pants off,' he added.