When Kim Mager sat across from Shawn Grate, she was expecting to interact with another sex offender, one of many from her decades-long career.

Mager, a 30-year veteran of the Ashland City Police Department in Ohio, had no idea she was face-to-face with a serial killer. She interrogated him for 33 hours over eight days.

“When I first started speaking to him, I didn’t find his personality to be that far off from other sex offenders, and I’ve interviewed many sex offenders,” the retired detective told Fox News Digital. “So, he was unremarkable to me. A lot of things he would say flowed like a typical conversation. His thought process seemed to be the same as anyone else.

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“But there was a difference,” she added. “That all changed when he spoke of his desire, his hunger. Those were his words — ‘a hunger to kill.’”

Mager collaborated with author Lisa Pulitzer to write “A Hunger to Kill: A Serial Killer, a Determined Detective, and a Quest for a Confession That Changed a Small Town Forever.” It details how Mager closed in on — and broke — one of Ohio’s most infamous serial killers.

“I’ve been asked at least 30 times to speak out about the case, and I’ve declined every single time,” said Mager. “But then, I was approached by a family member of one of the victims. That family member came up to me in tears, saying the victim was being portrayed so negatively by some podcasts. This family member was very upset. She said, ‘Please do something.’”

“I knew I had to share this story — the right story,” said Mager. “And it’s important to let people know that what these victims experienced, this could happen to them. … It could have been me.”

On Sept. 13, 2016, Mager was in the shower when her phone started ringing. It was her captain. Emergency dispatchers had received a 911 call from a woman who claimed she was kidnapped by Grate.

Mager rushed to the station to interview the woman. By then, Grate had been tracked down by investigators. He was arrested and charged.

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According to Mager’s book, Jane Doe had bruises all over her face, arms and legs. There were fresh scratches and others that had healed. Some injuries were bluish-purple, others swollen and red. Splashes of maroon took over her neck and upper torso. Her eyes were bloodshot, and her face was stained with tears.

“I felt the weight of what had happened to her,” Mager said. “It’s hard for victims to talk about what happened to them — harder than anyone could imagine. It’s something even more difficult than speaking with a suspect. But I needed to get everything I could to get him.”

As an experienced specialist in sex offenses, Mager was one of the officers assigned to Grate’s case.

“I didn’t recognize his name at all,” Mager admitted. “We were unfamiliar with him.”

Grate was known as a charmer and a drifter who was friendly to anyone he encountered. But that “nice guy” façade quickly faded in the interrogation room.

“My first impression was that he looked physically fit,” Mager explained. “He was muscular. Before you even made eye contact with him, the first thing you noticed was his physique. He also looked like he hadn’t showered.”

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“When we finally made eye contact, you instantly notice his blue eyes — these piercing blue eyes,” she said.

Like a real-life Clarice Starling from “The Silence of the Lambs,” she would sit alone in the interview room with the accused predator.

Mager soon learned there were other victims.

“He’s opportunistic,” she explained. “If an opportunity is there, he seizes it. … Looking at these victims, you might see two who look similar, and then you see someone who’s completely different.

“You have one who’s leading a life of faith, who has more faith in God than almost anyone I know,” she continued. “Someone who would never have a man’s phone number on her phone because she’s so sound in her beliefs. And then you had another who sold her body at times. These women all had different lifestyles. There is no one victim type other than the opportunity that was there, whether it came to him or he created that opportunity.”

Following Grate’s arrest, police discovered the remains of Stacey Stanley, 43, and Elizabeth Griffith, 29, in the vacant Ashland home where Grate had been living. Grate confessed to the murders.

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Stanley was described as someone who was down on her luck, Oxygen.com reported. According to the outlet, Grate made it seem like he was going to help her with a flat tire before he abducted and assaulted her.

Griffith was said to be struggling with her mental health and had gone missing.

According to the outlet, Grate confessed to the murder of 29-year-old Candice Cunningham, a woman he dated. He took authorities to a wooden area about 12 miles from Ashland where he dumped her body. He also confessed to killing 31-year-old Rebekah Leicy, who had issues with drugs. She was reported missing in February 2015.

The outlet noted Grate also admitted to killing 23-year-old Dana Lowrey, who had disappeared in 2005. Her remains were found in 2007, less than a mile from Grate’s home. She was selling magazines at the time. According to reports, it is believed that Lowrey was Grate’s first victim.

Doe said she met Grate in the summer of 2016. They would talk about the Bible, go on long walks and play tennis, the Mansfield News Journal reported. While Grate hinted he wanted more than a friendship, Doe said she turned him down and explained she didn’t believe in premarital sex due to her beliefs. Grate told her he respected her decision.

It was a lie.

Grate held Doe captive and sexually assaulted her “in every way imaginable.” While he was asleep, Doe managed to escape and call police.

Grate told Mager he wanted to know what drove him to kill.

“He was asking why he did it because he didn’t know,” Mager explained. “As we explored his childhood, he would come up with all of these different things that happened in his life but couldn’t definitively say any of those things caused it. … He asked me over and over, ‘Why did I do this? Why do you think I did this?’

“He talked a lot about … his relationships with his family,” Mager continued. “He talked about what he claimed was the promiscuity of his mother, who he said abandoned him. He talked about an incident when he was 4 years old. … He said he was on the sofa, watching cartoons that he could put on himself. But he wanted cereal, and he needed his mom’s help. He knocked on the bedroom door, and she didn’t come out. He knocked again. No answer.

“He said he knew that she was in the bedroom with someone. He wanted cereal, so then he began beating on the door. Finally, the door opened, and it was a stranger, a man he didn’t know. He said he ran back to his bedroom. But the man followed him and sat down on his bed. The guy said something to the effect of, ‘What’s wrong buddy?’ He said he began hitting the guy, attacking him, frustrated by the entire scenario.”

Grate claimed that growing up, he was close with his father, and the two bonded over baseball. However, an injury damaged his pitching arm, and he could no longer play with his father.

“He describes how his relationship with his father, the special thing they had shared, was gone,” said Mager. “He said he felt detached from his father from that moment on. … He spoke a lot about feeling abandoned.”

Mager admitted that Grate presented himself “as being remorseful,” but she still doesn’t know if it was genuine.

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Mager helped extract Grate’s confessions to five murders, kidnappings and multiple sex assaults across Ohio. He was dubbed “The Ladykiller” by the press due to his looks and charm. He is now on death row for the killings of two of the women in Ashland County. He’s also serving three life sentences.

Mager hopes the victims won’t be forgotten.

“These were daughters, mothers, sisters and friends,” she said. “Stacey Stanley loved cooking and her family. Candice Cunningham was always so happy and giggling. Rebekah Leicy was described by many as a loyal friend. Elizabeth Griffith was always determined to do the right thing and found joy in the little things. Dana Lowrey was a hard worker who also always tried to do the right thing.

“None of these women deserved what happened to them.”