19-year-old drove his car into a ditch on his way home from a party and was never seen or heard from again

Here are the chilling final words a teenager in the US told his parents before disappearing.

On 14 May 2008, 19-year-old student Brandon Swanson had been travelling home to his parents house in Minnesota after celebrating the end of his spring semester at a local college with a group of friends.

Instead of staying over at a friend's house, Swanson decided to make the journey back to his parent's home in the town of Marshall, southwest of state capital Minneapolis, in the early hours of the morning.

Swanson knew the route well as he regularly used it to commute to and from college, however this time he would not return home.

Brandon was just 19 years old when he disappeared (National Center for Missing and Exploited Children)

Just before 2.00am on 14 May, Swanson phoned his parents up to inform them he had driven his car into a ditch and could not get it back out. He added that he was uninjured but requested his parents come and pick him up.

After failing to locate their son at the location he'd given them, Swanson made the decision to walk towards lights, which he believed to be from a nearby town, and told his parents to meet him there.

Swanson had set off walking while remaining on the phone to his parents, however he would chillingly exclaim the words 'oh s**t' before the line went quiet.

The Swanson's would never hear from their son again.

Terrified, the teenager's parents and friends searched throughout the night while also attempting to ring his phone - with no luck. Swanson's mother, Annette, reported him missing to police in the nearby town of Lynd the next morning.

A missing poster for Brandon Swanson (National Center for Missing and Exploited Children)

After authorities finally begun their search for Swanson they would discover the teen wasn't in his originally assumed location of Lynd, but actually 25 miles (40 km) away in a different direction. After tracking his location through nearby cellphone towers, police were able to locate the student's car stuck in a ditch. No personal items or the car's keys were recovered.

Searches with sniffer dogs later lead police towards the Yellow Medicine River, however they lost the scent.

Authorities theorise that Swanson may have fallen into the river, however no trace of the teenager - or any of his physical belongings - have ever been found, leaving the case unsolved to this day.

Searchers were unable to locate Brandon or any of his belongings (Marshall Independent/Public Domain)

The initial response to her son's disappearance later saw Annette successfully campaign for the introduction of 'Brandon's Law' in the state, which requires police investigations into the case of a missing adult to begin as soon as it's reported.

Explaining her decision to push for the change, Annette explained that she had been motivated by the police reaction to her son's disappearance, saying: "I'm his mother and I knew something was horribly wrong."