Amazon has removed merchandise featuring the words “deny”, “defend” and “depose”, which were reportedly written on bullet casings found at the site of the killing of the UnitedHealthcare CEO, Brian Thompson.

Since last Wednesday’s fatal shooting, items such as T-shirts, hoodies, mugs, caps, pint glasses and more bearing the words “deny, defend, depose” have been available for purchase on online retail stores including eBay, Amazon, Etsy and other sites.

Reports citing law enforcement purport that the words “deny, defend, depose” were found written on the bullet casings at the site of the Thompson’s killing on 4 December in midtown Manhattan and may be a reference to the tactics critics say health insurance companies use to avoid paying claims. A New York Times report asserted the words on the bullet casings were “deny” and “delay”, calling to mind Delay, Defend, Deny: Why Insurance Companies Don’t Pay Claims and What You Can Do About It, a 2010 book that was critical of the rapacious, largely privatized US healthcare system.

Whatever the case, Amazon on Monday told the Washington Post that it had removed merchandise with that phrase from its website after the newspaper contacted the online retailer for comment.

In a statement to the newspaper, which is owned by Amazon founder Jeff Bezos, the retail company said that the products violated their guidelines. The statement stopped short of specifying which guidelines those were.

As of Tuesday morning, a search for the three-word phrase on Amazon now yields Delay, Defend, Deny by author and law professor Jay Feinman. It appeared to be sold out.

There are also several songs titled Deny, Defend, Depose available for purchase.

It is unclear how much of the Deny, Defend, Depose merchandise was bought on Amazon before the items were removed.

And while the items have been pulled from Amazon’s platform, lots of items featuring the phrase and words are still available on many other websites and online marketplaces, including eBay, Etsy, and TikTok as of Tuesday morning. Shoppers can buy a variety of items sporting the phrase, including clothing, water bottles, Christmas ornaments, bedsheets and more.

A spokesperson for eBay told the Washington Post that its policies do not ban the sale of items featuring the phrase Deny, Defend, Depose but “items that glorify or incite violence, including those that celebrate the recent murder of … Thompson, are prohibited”.

Etsy and TikTok did not immediately respond to requests for comment.

The killing of the UnitedHealthcare CEO on 4 December generated widespread anger online among those frustrated with the US healthcare system, leading some to voice their support for the shooter and even view him as a folk hero.

A recent report by the Network Contagion Research Institute at Rutgers University – which monitors online threats – found that six of the top 10 most-engaged posts on the social media platform X regarding Thompson’s murder either “expressed explicit or implicit support for the killing” or “denigrated the victim”.

The suspect, 26-year-old Luigi Mangione, had not yet been identified when the Deny, Defend, Depose merchandise first began circulating online shortly after Thompson’s murder. Other merchandise featuring stills from the surveillance footage was also being sold online – and a jacket similar to the one the shooter was wearing in surveillance video quickly sold out.

After Mangione was arrested and identified as the prime suspect in the case, his social media accounts quickly gained hundreds of thousands of followers.

Mangione was arrested on Monday in Pennsylvania and was arraigned later that evening on charges of five crimes in the state of Pennsylvania, including carrying a gun without a license, forgery, falsely identifying himself to the authorities and possessing instruments of crime.

Later Monday night, he was charged with murder by prosecutors in New York.