In criminal prosecutions, DNA is widely considered a smoking gun, but only in the absence of an identical twin.
Karen Steinhauser, a criminal defense attorney and adjunct law professor at the University of Denver, told The Associated Press such an argument is rare.
"I have never seen it, ever," she said. "The only time I have seen it was on 'Law and Order: SVU,'" the television show.
Steinhauser is not involved in the case.
In an Oct. 22 court filing, Lucas' attorneys said investigators picked the wrong sibling after discovering a DNA link to an unsolved attack on a young girl in Madison, Ala., in 2007, and another in Texarkana, Texas, in 2009.
The Fort Carson, Colo., officer has denied luring or trying to lure 11 girls into his vehicle in Colorado between 2009 and 2012. His attorneys have said the Alabama and Texas cases involve his twin brother, Brian Frederick Lucas, who the defense says has lived in both states.
Brian Lucas, who has not been charged in any of the cases, could not be reached for comment Saturday but investigators have said he has denied involvement in the alleged crimes.
Aaron Lucas' attorneys say an unidentified third man is responsible for the Colorado assaults.
Investigators say that a DNA test linked Aaron Lucas to the abduction of an 8-year-old girl in Colorado Springs and that he also matched biological material recovered in the Alabama and Texas cases. The Colorado judge has ruled that the out-of-state evidence will be allowed at trial.
Lucas is scheduled to appear in court Nov. 26. His attorneys did not return a message left by The Associated Press on Saturday.
Information from: The Gazette, http://www.gazette.com