"We've seen that more than 160 criminals were out on probation or parole for some other crime when they murdered a police officer over the last 10 years. That's about 16 officers per year who have been killed by criminals that should have been kept behind bars."
An area he said that has seen dramatic improvement over the years has been better emergency medical care.
"The way we treat shootings, the way we treat auto crash injuries has improved dramatically in recent times," he said. "As a result, those who might get injured who in the earlier times might have died from those injuries; they are now being saved because of the improvements in emergency medical care."