Heard, who had just filed for divorce, arrived at a Los Angeles courthouse that day to seek a temporary restraining order, showing up with a clear mark on her face, which she said Depp inflicted during a fight six days earlier.
Photographers captured the scene, and the allegations became tabloid fodder across the globe.
Depp says he never hit her, and now he is suing Heard for libel in Fairfax County Circuit Court in Virginia, US.
On Wednesday, jurors in the case heard from police officers who responded to the couple's penthouse immediately after the fight. None of the officers saw the red mark that was so prominent six days later.
Officer Tyler Hadden said Heard refused to talk to police and had no signs of an injury, although he acknowledged she had been crying and was red-faced.
"Just because I see a female with pink cheeks and pink eyes doesn't mean something happened," he said in a recorded deposition played for jurors on Wednesday.
Depp had already left the penthouse by the time officers arrived. Officers said they had no idea who Heard was, or that she was married to Depp.
Jurors heard similar testimony on Tuesday from an officer who accompanied Hadden to the penthouse.
An officer who made a follow-up visit that night, William Gatlin, testified on Wednesday he saw no injuries either, though he acknowledged his visit was brief and he got no closer than three metres from Heard.
Heard's lawyers, in their questions, have suggested Heard could have covered her injuries with makeup, because at that point she still wanted to protect Depp.
They also asked officers why they did not investigate a potential case of domestic violence more thoroughly.
The officers' testimony is some of Depp's best evidence that Heard contrived the allegations against her ex-husband.
It complements earlier testimony from witnesses who say they saw Heard and her sister practising fake punches in the days after the attack.
It is far from definitive, though. Heard's lawyers have yet to put their case, and some of her friends say they were at the penthouse when Depp allegedly attacked her.
And even if jurors were to conclude that Depp never assaulted his wife on May 21, they have heard evidence of other alleged assaults before and during the couple's brief marriage.
Depp sued Heard for libel after she wrote an op-ed piece piece in The Washington Post in 2018 referring to herself as "a public figure representing domestic abuse".
The article doesn't mention Depp by name, but his lawyers say the article defames him nevertheless because it is a clear reference to the highly publicised allegations Heard made when she filed for divorce in 2016 and obtained a temporary restraining order.
Jurors also heard recorded testimony on Wednesday from Christian Carino, an agent who represented Depp and Heard and was friends with both.
He said he believes the abuse allegations scuttled Depp's participation in a sixth Pirates of the Caribbean film, but he did not pin the loss of that film specifically on Heard's 2018 op-ed piece.
Heard's lawyers told jurors in opening statements that there must be proof that the Post article specifically damaged Depp's reputation for him to prevail in a libel case.
14°C