Editor's note: Paul Callan is a CNN legal contributor, a criminal defense attorney and a former New York homicide prosecutor, including in the "Son of Sam" case. He is a senior partner at Callan, Koster, Brady & Brennan, LLP. Callan spoke with CNN about the charges that Aurora, Colorado, shooting suspect James Holmes is facing.
(CNN) -- Can you explain the charges James Holmes is facing?
Paul Callan: Colorado prosecutors have charged the defendant, James Holmes, with 142 counts of criminal conduct for his alleged role in the Colorado movie theater massacre. The staggeringly large number of serious charges is not surprising given the number of victims in the case. (Twelve people were killed and 58 others injured.)
While prosecutors could have proceeded with a more streamlined case, they have elected the safer route of charging as many crimes as possible as the prosecution begins. The case can be streamlined later on if problems develop in proving some of the crimes listed. Additional charges may also be lodged in the future relating to the incendiary devices found by law enforcement authorities at Mr. Holmes' apartment.
Why is Holmes facing two charges for each person who was either killed or injured in the shooting? Is there a strategy behind this?
Callan: Prosecutors have elected to assert two counts of first-degree murder for each person who was killed as a result of the hail of gunfire in the Aurora movie theater. This approach is somewhat unusual.
The first of each of the murder counts alleges that Holmes "after deliberation" intentionally caused the death of his victims. This is the traditional premeditated murder charge that is used in cases of intentional murder throughout the United States. Prosecutors will seek to prove that the murders were planned and that Holmes formed an "intent" to kill his victims before pulling the trigger.
A second more unusual first-degree murder count was added for each victim charging that the manner in which the killings took place evinced "... an attitude of universal malice manifesting extreme indifference to the value of human life. ..." In many states, this is called a "reckless indifference" murder and is quite different from intentional, premeditated murder. It requires an act of callous and reckless indifference to the value human life which causes death.
An example might be a drunken driver who speeds down a busy city sidewalk, striking and killing pedestrians in the process. Even though the killings may not have been planned or even intended, the conduct is so grossly reckless and maliciously indifferent to the possibility that someone might be killed that the law says it is just as bad as premeditated murder. In fact, in Colorado intentional murder and extreme indifference murder both carry the same potential sentences: life imprisonment or the death penalty.
Prosecutors have hedged their bets by adding the "extreme indifference" counts because proving the intent to murder each individual victim may be problematic. Some victims may have been killed by ricochets, or it is even possible that Holmes' weapon was aimed at the screen when some of the fatal shots were fired. We won't really know all of the details until the evidence is presented.
Should Holmes' lawyers assert that mental illness prevented him from forming the specific intent to kill particular victims, these additional counts will give jurors an alternative theory of guilt. Firing a weapon of any kind in a crowded theater would easily constitute an act of "extreme indifference" murder under Colorado law.
Does charging that way leave open the door for a capital case? Is there another intent behind that second charge?
Callan: The second charge was not added to increase the likelihood of capital punishment. Although the penalty can be imposed for extreme indifference murders, it is more commonly imposed in cases of intentional premeditated murder. Prosecutors have taken this approach to ensure that each victim's family can find some measure of justice in a guilty finding on at least one count relating directly to their loved one's loss.
Prosecutors will be confident that even if the intentional murder of a victim cannot be established, the killing was most surely caused by "extreme indifference to the value of human life" when gunfire was directed at the interior of a crowded movie theater.
The same two-count theory was used in the form of attempted murder counts lodged for many other victims who survived the tragedy but almost suffered death. The prosecutors' rationale for this approach would be the same as with the murder counts.
™ & © 2012 Cable News Network, Inc., a Time Warner Company. All rights reserved.