Topeka ? In the summer of 1974, 13-year-old Liz Wilson disappeared after cutting through the grounds of a Prairie Village high school while returning home from a swimming pool. Six months later her skull and several bones were found at a construction site several miles away.

Police at the time questioned the school custodian, John Henry Horton, who was working there when the girl disappeared. But the case remained unsolved until he was arrested in 2003 and convicted of first-degree murder in 2005 by a Johnson County jury.

On Friday, the Kansas Supreme Court unanimously reversed the conviction, saying the trial court improperly admitted evidence of an alleged prior crime by Horton, 59, who lived in Independence, Mo., at the time.

However, the court said the state could file new charges against Horton and use physical evidence taken from Horton’s car, including hair and bottles of chloroform and ether, police records and testimony of an accident reconstruction expert.

Johnson County District Attorney Phill Kline said he’s reviewing the ruling and will check the facts of the case and consult with the family before deciding what to do.

“District Attorney Kline is committed to seeing that justice is served in the case,” said a statement from his office.

Rick Guinn, who prosecuted the case, expressed disappointment over the ruling. He is chief counsel to Attorney General Paul Morrison, who was Johnson County prosecutor when the case was tried.

“It was a difficult and hard-fought case, and we hope that District Attorney Kline will decide to retry it. And our hearts go out to the victim’s family,” Guinn said.

Horton is at the Norton Correctional Facility and won’t be immediately released because the court’s order won’t become final for 30 days, giving prosecutors time to file new charges. The death penalty wasn’t on the books at the time, so it’s not an option.

In a second trial, the court said what wouldn’t be allowed is the testimony of a woman who was 14 at the time of the disappearance and lived across the street from Horton in 1974. The woman said she believed she had been sexually molested on a golf course after Horton held a rag with chloroform under her nose until she passed out. She said she went to the golf course with Horton and his 15-year-old niece to get high.

The woman also testified she was aware of the girl’s disappearance and saw police at Horton’s house but never told anyone about the golf course incident until contacted by police in 2002, after the investigation was renewed.

The state’s theory was that Horton used chloroform to kidnap Liz Wilson on July 7, 1974, to molest her and accidentally killed her with too much chloroform. Her family lived about three or four blocks north of the pool, and Shawnee Mission East High School was between her home and the pool.

In January 1975, a contractor found a human skull at the construction site, which once was an alfalfa field near Lenexa. Police then found several human bones. A month later, a farmer who baled alfalfa the previous summer found a human bone in a bale.

The Wilson family recovered the remains and buried them in Iowa. DNA testing in 2003 confirmed the remains belonged to Wilson.

The court said the golf course incident shouldn’t have been admitted as evidence because of the state’s failure to demonstrate sufficient similarity between the victim’s disappearance and the witness’ allegation of sexual abuse. It said the only similarity appeared to be the girls’ ages. The woman also testified at Horton’s preliminary hearing.

“We appreciate the tragic circumstances surrounding the death of Liz Wilson and the need for finality and accountability of those responsible for her murder,” Judge Eric S. Rosen wrote for the court.

However, the court said any conviction must be based on evidence that is relevant and satisfies the basic requirements of admissibility.

“Here, the trial court ignored a basic standard which has been part of the Kansas law for over 40 years by failing to require the state to show not just a sufficient similarity but any similarity between Liz Wilson’s disappearance and death and the alleged prior bad act,” the court said.