DECATUR — A jury of six men and six women failed to reach a verdict in the case of Danny Dietz Jr., 42, who was charged with sexually assaulting a girl during a period of about five years, beginning when she was younger than 13.

After deliberating for about five hours Thursday, the jury foreman told Associate Judge Timothy Steadman the jury was deadlocked. After eliciting a motion from a prosecutor, the judge declared a mistrial at 2:11 p.m.

After listening to two days of emotionally charged testimony, the jury began its deliberation late Wednesday afternoon.

In her closing argument, Assistant Public Defender Karen Root argued that the jurors should focus on the fact that both the victim and the eyewitness to Dietz’s sexual assault lied at the time the case was first reported.

“Danny Dietz never lied,” Root asserted. “There is no physical evidence. There are no movies or videos. You have nothing but the old ‘he said, she said.’ ”

Root, who often presents alternate stories in her cases to explain why her clients should be acquitted, told the jurors the two teens made up the stories to avenge something he had done to them.

She said the victim and the eyewitness had plenty of time to get their stories straight about a 2010 rape, which was first reported to a nurse by the witness, a relative of the victim.

The report of that incident led to revelations about hundreds of other incidents of criminal sexual assault.

“It starts with a lie,” Root told the jurors.

In her rebuttal, Assistant State’s Attorney Mary Koll questioned how the two teens could have conspired to lie about the 2010 assault. The victim initially denied that any abuse occurred, but later confirmed details that meshed with her relative’s account.

“If this was a conspiracy, it was a highly sophisticated conspiracy,” Koll told the jurors.

Koll argued that if the victim lied on the witness stand, the jurors would have to believe that she delivered an “Oscar-winning performance.”

The victim trembled and sobbed during most of her testimony. At one point, she broke down, and a recess was called.

Koll, who prosecuted the case along with Assistant State’s Attorney Elizabeth Dobson, commended the victim for her bravery for testifying in graphic detail in front of the defendant and many strangers.

“Her emotions were raw and real both here when she testified and at the Child Advocacy Center,” Koll said. “What we see in that video (an interview with a sheriff’s detective) is the victim going back to those experiences and struggling to put words to the horrors that nobody should have to experience.”

Dietz was returned to jail, where he is also awaiting trial on two felony cases of harassment of witnesses. Prosecutors will decide whether to retry the criminal sexual assault case. Dietz, who is being held on $400,000 bond, is due in circuit court Oct. 16 for hearings on his three cases.|421-6985