New DNA evidence has emerged in relation to the murder of UnitedHealthcare CEO Brian Thompson after the gunman left an item behind when he fled.

Authorities are still searching for clues about the homicide of Thompson, who was shot three times outside a hotel in New York City on Wednesday morning (4 December).

The shooter escaped on foot after the murder, heading down an alley and getting on an e-bike before heading into Central Park, where CCTV footage lost track of them.

Bullet casings of the shots from the assassin read ‘deny’ ‘defend’ and ‘depose’ on them, which is said to be a connected to the book titled Delay, Deny, Defend, which is famous for criticising the way that health insurance companies operate.

The phrase ‘delay, deny, defend’ is used by those that do not agree with the American health insurance system, as they say they use it to avoid paying out claims.

Thompson was the CEO at UnitedHealthcare, the largest provider of Medicare Advantage plans in the US, and made $281 billion (£219 billion) in revenue last year, according to The Washington Post.

An image of the suspected killer was later released by the New York Police Department (NYPD), urging Americans to help look for the individual.

However, after escaping, items such as a phone and water bottle were recovered from the scene of the crime, which are being investigated for DNA.

But a new piece of evidence is shrouded in an air of mystery – though it could be crucial in the investigation.

A photo of the suspected killer was released to the public (NYPD)

It is not clear where the new evidence came from, but it came after investigators searched the HI New York City Hostel on Manhattan’s West Side, which is where the suspect is said to have stayed prior to the shooting, The Sun reports.

Newly released footage shows the suspect leaving an item behind, with this breakthrough following reports that claimed that the gunman had arrived in New York in November on a Greyhound bus from Atlanta, according to ABC 7 – with a Greyhound spokesperson telling the publication that they were cooperating with the NYPD investigation, however, could not ‘provide further comment at this time’.

The individual can be seen getting off the bus at Manhattan’s Port Authority Bus Terminal on 24 November. It was also reported that he’d checked into the hostel on 30 November by using an ID that wasn’t his.

The investigation is entering its third day – though police have not yet released a name for the potential suspect.