Trump made the remarks in an August 31, 2020 Fox News interview:

The police are under siege because of things – they can do 10,000 great acts, which is what they do, and one bad apple, or a choker – you know a choker, they choke, shooting the guy in the back many times. Couldn’t you have done something different? Couldn’t you have wrestled him? In the meantime, he might’ve been going for a weapon. And there’s a whole big thing there. But they choke. Just like in a golf tournament, they miss a three-foot putt.

The interview came after months of protests and riots after George Floyd was killed by police on video. Trump had threatened the use of “vicious dogs” and “ominous weapons,” and warned that “when the looting starts, the shooting starts.”

USA Today – Trump tells Ingraham some officers ‘choke’ during shootings, saying ‘They miss a 3-foot putt’
The Hill – Trump compares police who use force to golfers who ‘choke’
Business Insider – Trump denies fringe theory that a series of ‘mini-strokes’ prompted his unannounced trip to Walter Reed hospital last November
Forbes – Trump Denies ‘Series Of Mini-Strokes’ Prompted Surprise Walter Reed Visit