Hansen was accused of using a rubber mallet to attack the teen during the afternoon of Sept. 24 as she was walking on the Iron Horse Park Trail.
“The victim’s screams for help were heard by a neighbor, who witnessed the defendant attacking the girl,” Montgomery County Prosecutor Mat Heck Jr. stated in an Oct. 5 news release announcing Hansen’s indictment.
The teen suffered serious cuts on her head, which prosecutors said required dozens of staples. The arrival of the man who lived near the park and heard the girl’s screams halted the attack, police said.
The plea agreement was filed the same day a decision on a motion to suppress was entered by the judge, according to court records. The defense had asked the judge to disallow statements allegedly made by Hansen to police. The judge did suppress some statements but allowed others.
The judge had previously ruled that Hansen was competent to stand trial.
Hansen is currently incarcerated in the Montgomery County Jail on $500,000 bond.