Fast-fashion giant Shein has launched an investigation after an image of Luigi Mangione – accused of murdering UnitedHealthcare CEO Brian Thompson in New York last year – was used to model a shirt.

An image with his likeness, which appeared to show him wearing a white, short-sleeved shirt, appeared on the fast-fashion website until its removal.

It is thought the product he appeared to be modelling was on sale for just under $10 (£7.50).

A spokesperson from Shein told BBC News: “The image in question was provided by a third-party vendor and was removed immediately upon discovery.

“We have stringent standards for all listings on our platform”, they said.

“We are conducting a thorough investigation, strengthening our monitoring processes, and will take appropriate action against the vendor in line with our policies.”

It is not known for how long the image was used, or who was selling it on the Chinese company’s website.

Many online have speculated the image was created using artificial intelligence (AI) – but it remains unclear how the picture was made.

In April, Luigi Mangione pleaded not guilty to all federal charges brought over the fatal shooting of Mr Thompson.

The 26-year-old, who was arrested in December, faces the charges of murder and stalking.

His not guilty plea means he will face trial and prosecutors are seeking the death penalty if he is convicted.

Public reaction to Mr Thompson’s killing has shed light on privatised healthcare, and some have celebrated the accused murderer as a folk hero, with supporters gathering outside the courthouse during his hearings.

The case has gripped social media, fuelled by anger towards America’s private health insurers.

The start of his legal battles prompted anonymous donors to chip in thousands of dollars towards his defence through various online fundraisers.

Etsy was flooded with clothes featuring his name, while Amazon pulled similar products from their site.

The McDonald’s worker – alleged to have turned him in – has become a target for online hate, while the fast-food franchise itself has been spammed with bad reviews.

The police department in Altoona, Pennsylvania, that arrested him even received death threats.

Luigi Mangione’s appearance, which he showed off in shirtless social media posts, is now clearly part of the appeal, said cultural critic Blakely Thornton in December.

People in the US are effectively “programmed” to trust and empathise with men who look like Mangione, he said.

This is not the first time his name or likeness has caused controversy for a company.

In December, the BBC complained to Apple after the tech giant’s new iPhone feature generated a false headline about the accused murderer.

Apple Intelligence used AI to summarise and group together notifications.

The summary falsely made it appear BBC News had published an article claiming he had shot himself – when he had not.

A month later, Apple suspended the feature after the error and other mistakes.

His lawyers have not commented on the use of his image on Shein.

Additional reporting by Liv McMahon