Centennial - The former graduate student accused of opening fire on moviegoers in a Denver-area screening of the latest Batman movie 10 days ago was formally charged on Monday with 142 criminal counts, including first-degree murder charges.

James Holmes, 24, was charged with 24 counts of murder and 116 counts of attempted murder.

He was also charged with one count of possession of explosives. Authorities say he booby-trapped his apartment.

The charges were formally presented as Holmes, made his second court appearance since his arrest moments after the massacre during a packed showing of The Dark Knight Rises shortly after midnight on 20 July.

Twelve people were killed, and 58 people were wounded or injured.

Holmes was arrested shortly after the rampage during a midnight showing of the movie.

Legal analysts expect his case to be dominated by arguments over his sanity.