Lawyers for the Colorado theater shooting suspect filed at least six new constitutional challenges to the state's death penalty laws on Monday.
In the new motions made public on Tuesday, lawyers for James Holmes argue that the death penalty has been arbitrarily imposed in Colorado, is not a deterrent, is used so rarely that it's unconstitutional and that its use is cruel and usual.
"Imposition of the death penalty is rare, unusual, freakish, and inconsistently applied throughout the State of Colorado," defense lawyers wrote in a motion.
Another motion asked that victims not be allowed to testify when the jury is deciding punishment and that opponents of the death penalty be allowed to sit on Holmes' jury.
One of the motions also cites a 2009 study by the University of Colorado titled, "Do Executions Lower Homicide Rates? The Views of Leading Criminologists," published in the Journal of Criminal Law and Criminology that found, "94 percent agreed that there was little empirical evidence to support the deterrent effect of the death penalty."
Colorado currently has three men sitting on death row and has only executed one person since the death penalty was declared unconstitutional in 1972. The death row inmates -- Nathan Dunlap, Sir Owens and Robert Ray -- were all sentenced in Arapahoe County.
Holmes has pleaded not guilty by reason of insanity to charges that he opened fire on a Colorado theater, killing 12 people and injuring 70 more in July 2012.