An Amazon delivery driver was filmed appearing to spit into his hand before wiping it on a package he had just left on the doorstep of a customer.
The recipients say they noticed the box was wet when they went to retrieve the delivery and at first assumed a dog had urinated on it.
Checking video footage from their doorbell camera, they were 'horrified' to find what had really taken place.
The video was posted on social media to warn others following the incident in Los Angeles, which the recipient described as 'reckless' during the current coronavirus pandemic.
The customer quickly tried to decontaminate themselves after handling the package, before contacting the police and Amazon themselves to report the footage.
Neighbour Tammy Minoff told Fox10 she was glad they shared the clip, saying: "It's horrifying, it's upsetting.
"The proof was in the pudding seeing that video and they just wanted us to be warned and to be on the lookout.
"I hope it's really taken seriously by Amazon and everyone in charge. It's serious."
Amazon told Fox10 the driver is no longer delivering for the company and in a statement said: "We are aggressively investigating to understand what may have occurred in this situation.
"If it truly was a malicious act by the driver, we will be sure he is held accountable, up through and including law enforcement action."
The Mirror has contacted Amazon for comment.
Yesterday it was reported the United States now leads the world in the number of confirmed coronavirus cases, with 82,000 people infected according to a running count by Johns Hopkins University.
That puts the number of those testing positive for Coronavirus ahead of China, with 81,000, and Italy, with 80,000.
New York alone has 46,262 cases, where 606 people have lost their lives, with doctors working in the state describing 'apocalypic' scenes as the city becomes the pandemic's 'new Italy'.