James Holmes in his first court appearance, July 23 2012.
(CBS News) -- The well-armed shooter in the Aurora movie theater massacre had a hit ratio twice what a police officer might have engaging with armed assailants in a street setting.
That suggests, says senior correspondent John Miller, that the suspect - who is believed to have planned his assault with precision - must have practiced shooting prior to the attack on the theater audience last Friday.
James Holmes, who made his first court appearance Monday, will face charges in the deaths of 12 people at the Century 16 theater. Fifty-eight others were also injured in the spree, most by gunfire.
"Here's an individual who we see kind of lolling in court but who went into that theater, actually shooting and hitting with bullets more than 52 people of the 70 injured," said Miller on "CBS This Morning." "Here's a guy who went in with what we think was about 100 rounds; that gives him a 50 percent hit ratio.
"From law enforcement, when you go on the range and you're shooting at a paper target - it is standing still and waits for you - that's a 90 to 94 percent hit ratio in a lot of places. In combat shooting in the street, police officers often hit in ranges of 21 to 25 percent of their targets."
In addition, Miller said, the shooter was able to maintain that high ratio with three different types of weapons.
"He chose the shotgun, which you know the expression the 'shotgun effect,' it's blasting out. That is one weapon, but he transitioned neatly from that to the AR-15 [semi-automatic assault rifle], which had that drum magazine of 100, which we believe jammed. And then he transitioned from that to the pistol until he was out of that ammunition.
"He was working effectively with three weapons," Miller said. "So the idea that transitioning from three weapons he could have a 50 percent hit rate on moving targets in a confusing environment really goes to the idea that he's been practicing somewhere."
Last month Holmes applied to become a member of the Lead Valley Range in Byers, Colo. However, the gun range's owner denied his application, owing to what he characterized as a "bizarre . . . freakish" voice mail greeting he heard when responding to Holmes' application that he told his staff not to accept him.
Miller said investigators have been to two gun ranges Holmes tried to get in to but didn't. "They're pretty sure that there's one out there that he actually got to spend time at, and they're still looking for it."
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