Would it have been better if the killer had used poorly-designed bullets?
Bullets intended to maim but not kill?
Shoot, he probably used a 9mm: it’s surprising anyone actually died.
I can understand liking big power, but the 9mm is more than capable. It's what the Israelis standardized on in their fight for national survival. It's plenty powerful and lethal. Typically as powerful as a 45 ACP in terms of muzzle energy, and well-documented to get the job done.