Washington, July 23 : `Dark Knight' massacre suspect James Holmes will try to dodge the death penalty with a desperation insanity defense, but is likely to fail, legal experts have said.

Holmes, 24, allegedly opened fire during a packed midnight screening of Batman film `The Dark Knight Rises,' killing nearly 12 people at a movie hall in Denver.

According to Colorado legal expert, it's a certainty Holmes will try pleading insanity.

"The only real defense would be the insanity defense," the New York Post quoted former federal prosecutor Rick Kornfeld, as saying.

"The first order of business for his defense lawyer is to get a grasp of Holmes' mental status," he said.

According to Craig Silverman, former prosecutor in the Denver District Attorney's Office, to mount a successful insanity defense, the attorney representing Holmes must show that he could not tell the difference between right and wrong and that he does not understand the charges against him.

"He would have to prove that he lacked the capacity to distinguish right from wrong," the report quoted Silverman, as saying.

"Insanity would apply if this guy really thought he was a character in a movie," he added.

According to the paper, experts said that Holmes is likely be represented by public defenders.

"I would expect a public defender to jump in. This is not Texas. These lawyers are good and well-compensated," Silverman said. (ANI)