State police troopers have a unique way of looking at the local landscape, and Dan McKnight, Troop D, retired, is no different.

“A police officer knows the county by bodies. When I drive through Butler County, I know I had a fatal accident here and a suicide there,” McKnight said.

“Every time I drive to New Castle, I think of Patty Desmond.”

Patricia Desmond was a 15-year-old girl living with her widowed mother and five siblings in a rented house on McCalmont Road in Butler Township in the mid 1960s.

On Dec. 5, 1965, Desmond had an argument with her mother, who did not approve of her dating married scofflaw Conrad Miller, 19, so she sneaked out of the house to meet her paramour.

It was the last time her mother would lay eyes on her daughter.

State police troopers have a unique way of looking at the local landscape, and Dan McKnight, Troop D, retired, is no different.

“A police officer knows the county by bodies. When I drive through Butler County, I know I had a fatal accident here and a suicide there,” McKnight said.

“Every time I drive to New Castle, I think of Patty Desmond.”

Patricia Desmond was a 15-year-old girl living with her widowed mother and five siblings in a rented house on McCalmont Road in Butler Township in the mid 1960s.

On Dec. 5, 1965, Desmond had an argument with her mother, who did not approve of her dating married scofflaw Conrad Miller, 19, so she sneaked out of the house to meet her paramour.

It was the last time her mother would lay eyes on her daughter.

The twists and turns of the decadeslong case are available for public perusal in the new book “Child Last Seen: The Search for Patty Desmond.”

Author Maureen Boyle, who wrote “The Ghost: The Murder of Police Chief Greg Adams and the Hunt for His Killer” about the search for and capture of Donald Eugene Webb, said she learned of Desmond’s disappearance and murder while talking to McKnight about the Greg Adams case.

“He mentioned ‘Oh, there’s this other case that is really fascinating,’” Boyle said, “and that is the case of Patty Desmond.”

Boyle said that Patty left the rented family home without a coat or purse and was picked up by Miller and some friends of his after her fight with her mother, Anna Desmond, over her relationship with Miller.

Boyle said Miller, who was married to a girl he had impregnated at age 16 and with whom he was raising that daughter, dropped the friends off and drove Desmond to Muddy Creek Township.

After some interaction with the friends who had been in the car when Desmond was picked up, the couple spent time hanging out at a strip mine owned by the Stanford Mining Co. in the township.

Anna Desmond reported her daughter missing to Butler Township Police, who picked up Miller the next day for questioning.

Miller told the officers that Desmond told him she was pregnant and the two had an argument. Miller said he dropped Desmond off at the Connoquenessing Volunteer Fire Department fire hall at 2 a.m. so she could access the nearby home of her friend, Mary Rice.

But Rice said Desmond never appeared at her house that night.

“That’s the story he stuck with for years,” Boyle said.

She said the Desmond family lived in that gray area of not knowing whether Patty was dead or alive, and naturally clung to hope, although they must have known in the back of their minds that Miller, who had a criminal record, had murdered their loved one.

“Patty was very naive,” Boyle said. “She was bullied, so this guy, when he was paying attention to her, it made her feel better.”

In addition, Miller’s looks in 1965 were likened to that of film heartthrob James Dean.

“She was really susceptible to something like this,” Boyle said. “Young girls make mistakes.”

In the years that followed, Butler County residents reported seeing Desmond at various locations.

“And of course, it wasn’t her,” Boyle said. “And Conrad Miller continued to run afoul of the law.”

After Desmond’s disappearance, he was charged and convicted of a brutal rape in South Carolina, where he served time.

“When he got out of jail there and came back to Pennsylvania, he was wanted for a parole violation from burglary charges,” Boyle said.

Anna Desmond continued to carry that shred of hope that her daughter was a runaway who chose to live elsewhere — not interested in contacting her family — until 22 years after her disappearance.

State police received a call from a very credible source who gave a location of Desmond’s body.

McKnight said the county district attorney at the time, David Cook, recommended troopers enlist the services of a forensic anthropologist in searching for the girl’s remains.

McKnight and his co-investigators, Glenn Hall and Ted Schwartzlander, contacted the University of Pittsburgh, and a lead anthropologist and a group of graduate students indeed located the bones of Patty Desmond near New Castle, Lawrence County, in bizarre circumstances.

Desmond’s dentist did not have X-rays of her teeth, but did keep detailed notes and had examined her in the days before her disappearance.

“He looked at the jawbone and the tooth that was attached, and he said that was her,” McKnight said.

Using all the evidence at hand, troopers filed charges against Miller including third-degree murder at the district magistrate’s office in Slippery Rock.

“The vice department arrested him walking back to his apartment down near the (then-Butler Junior High),” McKnight said.

Miller did not resist.

“He knew why he was being arrested,” McKnight recalled.

Miller’s attorneys struck a plea deal for a 14-year prison sentence, and Judge John Brydon, who was the district attorney when Desmond went missing, was the sentencing judge in April 1988.

“He made it a point to have Conrad admit in court that he killed her,” McKnight said.

But Miller never revealed how or exactly when Desmond died.

“He showed no remorse whatsoever,” McKnight said.

McKnight and Hall gave Patty’s mother the news she had been dreading for more than two decades.

He said sharing the news with her was emotional for all three.

Boyle said Anna Desmond had experienced a full measure of sorrow in her life, as her husband was killed at age 39 after falling and suffering a fatal head wound on Broad Street in 1956.

Anna Desmond performed whatever work was necessary to support her family in the following years, including manager at Edward’s Dairy Queen beside Butler High School.

“Everyone I talked to about Anna said she was a very hardworking widow who was really trying to keep things together for the kids,” Boyle said.

McKnight said neither the Desmond family nor investigators were pleased with the 14-year sentence Miller received, but he understands the reasoning for the plea deal.

“If it went to trial, you only need one juror to say ‘What if that wasn’t Patty Desmond?’ and he walks free,” McKnight said.

Boyle said Miller was denied parole in 1994, and served his entire sentence before being released in June 2001. She said he now lives with a woman in McKeesport.

Boyle said she decided to write the story of Patty Desmond’s demise because it is not a tale familiar to many Butler County residents, the inclusion of Pitt graduate students in recovering her remains, and the decades of worry endured by Anna Desmond, who was buried with her daughter’s remains in August 1994.

“I learned an awful lot about forensic searches, the recovery of remains and the science behind it,” Boyle said.

McKnight said Miller’s sentencing resolved two of the three missing person cases he worked on during his years at Troop D in Butler.

The case of Chief Adams was another of his cases, and he hopes the disappearance of 8-year-old Cherrie Mahan in 1985 in Winfield Township will be solved during his lifetime.

McKnight said Boyle’s work is an accurate and fascinating retelling of the case of Patty Desmond.

“She wrote the book on Donald Eugene Webb and she followed the facts, and she followed the facts in this case,” he said.