Gunman jailed for life for killing 12 people during Batman screening

A gunman who killed 12 people during a screening of Batman in a US cinema has been jailed for life.

James Holmes will serve life with no parole for the killings in July 2012, but was spared the death penalty after a jury failed to reach a unanimous verdict.

The 27 year old opened fire inside a packed premiere of The Dark Knight Rises in Aurora, Colorado, injuring 70 along with those killed.

As well as the sentence for the murders, Judge Carlos Samour Jr handed Holmes an additional 3,200 years for attempted murder and an explosives conviction.

Holmes stockpiled guns and ammunition and mapped out the Aurora theater complex to determine which auditorium would allow for the most casualties. He even calculated police response times.

"It is almost impossible to comprehend how a human being is capable of such acts," Judge Samour. said.