>Paramedics were called and injected McClain with ketamine, but they incorrectly estimated his weight, giving him more than 1½ times the dose he should have received. He got 500 milligrams because they thought he weighed 220 pounds, but he weighed only 140 pounds and should have received 315 milligrams.

https://www.latimes.com/world-nation/story/2020-08-22/ketami...

It is a matter of record that they injected him with 50% more than he ought to have received. As for your claim. It's not merely that this isn't true it isn't so far as I can discover even claimed by the police.

It's not even clear what you mean by the words "the prosecution" he didn't get tried for anything whatsoever by dint of being already dead because they screwed up and provably killed him.