Christian Cooper captured part of the exchange in a now-viral video that was posted to Twitter by his sister. The woman, later identified as Amy Cooper, is shown on video asking Cooper to stop recording her, or she was going to call the cops and tell them "there's an African American man threatening my life." She repeated the statement several times, each time sounding more distressed, while appearing to call 911 dispatch.
Use of a "Karen" meme more than a little forgiving. If she'd actually reported that he was threatening her life, she could have gotten him killed.* He's black and phones often turn out to be a "shiny object" that a scared cop thought "might have been a gun." Oopsie-daisy, another dead black guy; officer just doing his job. You know the drill.
If her life is ruined, it's her own damn fault. Dogs do need to be leashed there, and she was threatening to make a call that really could have gotten the guy killed. His best case scenario if she had actually reported that? Getting hauled off to jail, likely after getting roughed up, and only released later if the recording survived.
* Hell, there's another thread on how sitting in a car while police suspected a black man of a "forgery in progress" got the man killed - they kneeled on his neck until he died.