Updated

An Army artillery officer accused of a series of sex assaults for which he'd planned to blame his twin brother changed his mind Tuesday and pleaded guilty to the charges.

1st Lt. Aaron Lucas, who had been stationed at Fort Carson, Colo., faces 20 years to life in prison. His sentencing is scheduled for February 28.

Earlier this month, case judge David Shakes ruled that Lucas's attorneys could argue that the defendant's identical twin brother, Brian Lucas, committed the attacks on 11 girls between the ages of 4 and 10. Shakes said that it was the jury's role to decide if the defense was convincing. A trial had been scheduled for January.

Defense attorney Ted McClintock told the Colorado Springs Gazette that Lucas had changed his mind and made the guilty plea because "he wanted to do the right thing. He loves his family. He doesn't want to create problems for them."

Lucas had been linked by DNA to the June 2012 abduction and rape of an 8-year-old girl, as well as similar assaults in Texarkana, Texas in 2009 and Madison, Alabama in 2007. The defense's theory was based on the theory that since identical twins share DNA, the physical evidence would not prove Lucas' guilt beyond a reasonable doubt.

Lucas was charged with crimes ranging from kidnapping and rape to indecent exposure in connection with the attacks that took place in El Paso County, Colo. between 2009 and 2012. Authorities said the attacks stopped during a yearlong period while Lucas was deployed to Afghanistan.

As part of his plea agreement, Lucas waived extradition to Texas for the 2009 assault. Prosecutors in Alabama agreed not to charge him for the assault in that state.

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