How detectives got 'The Package Killer' to confess to decades-old murders

DNA from Robyn’s case led O’Fallon Detective Jodi Weber to Muehlberg in the spring of 2022.

He was already serving a life sentence for the murder of a man who tried to buy a car from him in 1993.

On June 30, 2022, she finally got the chance to confront him.

At 11:28 a.m., his 6-foot-4 frame walked through the door where Weber and St. Charles County Prosecuting Attorney’s Office investigator Mike Harvey were waiting for him. He rested a cane in front of him and plopped into a chair wearing grey prison scrubs.

“How are you today?” Weber asked.

“OK, good, I just woke up,” he said.

And he wasn’t in the mood for small talk.

“I guess you don't get any visitors,” Weber said.

“No, so get to the chase, what's going on?” Muehlberg said.

Ten minutes in, Weber pulled her ace.

She told him she had his DNA at Robyn’s scene.

“Does that ring a bell, you know, Robyn?” Weber asked.

“No, I don't remember,” he said.

She tried using his life sentence as leverage to get him to talk.

“I don't know how they give you anything more,” Weber said.

“Uh, yeah,” he chuckled. “The death penalty.”

Muehlberg kept asking if he was being charged with the murders.

“If you’ve got the evidence, why are you talking to me? Charge me with something,” Muehlberg said.

Weber explained why she wanted more.

“This is a case that’s gone unsolved for 32 years, right? Not one detective back in the early nineties, 40 to 50 detectives working on this, were not able to solve it. None of those guys, with all of their training and experience and all the training and everything. They weren’t able to solve these cases, so that’s why I want to learn as much as I can about you because you got past all of them,” Weber said.

The detective also told him how much she wanted to give answers to Robyn’s children and family.

Muehlberg didn’t budge.

“I mean, all the traces of DNA on a prostitute, I’m sure I’m not the only one she ever had sex with,” Muehlberg said.

Weber and Garvey persisted, tugging at whatever strings of empathy he might have.

“We just want to be able to tell these people, ‘Yes, we talked to Gary, he was straight up,’” Weber said.

“You know, I understand the bit about closure,” Muehlberg said. “Everybody has devastation. I lost a brother in Vietnam. The day he was buried for me was closure.”

“Wouldn’t you want to know exactly what happened?” Harvey asked.

“He died in war, I’ve accepted it, I’ve moved on,” Muehlberg said.

Forty-seven minutes in, Muehlberg had enough. He suddenly accused Harvey of “patronizing” him and abruptly announced, “We're done talking, we're done talking.”

Even if she wasn’t going to leave with a confession that day, Weber had to leave with a fresh DNA sample to make the evidence official.

Muehlberg wasn’t in the mood for that, either.

“I'm not giving you anything,” he said.

“We don't want to do it by force, but we can,” Weber said, summoning a corrections officer. “We didn't want to do it this way.”

As soon as the guard appeared, Muehlberg complied.

Weber left her business card for Muehlberg.

He refused to take it.

Five weeks later, the detectives went back.

This time, Weber brought letters from all three prosecutors where his victims were found — St. Louis County, Lincoln County and St. Charles County — pledging not to pursue the death penalty. She also gave him her word that he would not be moved out of the Potosi Correctional Center.

“I got you what you wanted,” Weber told Muehlberg, as he took a seat across from her where at the same table where he had lied to her before.

He reviewed the letters.

“So you've been thinking about this since we left last time?” Weber asked.

“What do you think?” Muehlberg said.

“Nonstop, huh?” Weber asked.

“Yeah,” Muehlberg said. “I mean, I'm old enough and health-wise, even with the death penalty, I would pass away before I got there. OK, so now what?”

“So, I'd like to start with Robyn,” Weber said. “Do you recall the mattresses?”

“Yeah. Yeah. Yeah. So apparently it happened in my house up in Bel-Ridge,” Muehlberg said.

He paused.

“It's painful as hell,” he said.

Muehlberg talked for nearly three hours but recalled very few details.

“Do you remember doing it?” Weber asked.

“Vaguely. I mean, I’m thinking I had sex with her and paid her,” he said.

Weber told him investigators also found some of his clothes with Robyn’s body, but forensic technology wasn’t advanced enough to tie them to him at the time.

“If I had any of my clothes in there, then it must have been subconsciously me asking for help or something, or to be caught,” he speculated.

He told detectives he kept some of the victims alive for a day or two.

He told them there weren’t any others.

And struggled for an explanation for it all.

“I've done things I'm damn proud of,” he said.

“Of course you have,” Harvey said.

“This ain't one of them,” Muehlberg said.

He clammed up almost every time the detectives prodded him to remember details only the killer would know.

“I'm sure I'm not the only one that tried to suppress this kind of stuff, pretend it never happened,” he said.

Later, he continued: “I come from good family, good people. I've always tried to do, maybe not the right thing, but the proper thing…I just hope someday I can figure out why. A lot of soul searching there has been over the last 30-some-odd years.”

“I bet, did you think about these at all over the last 30 years?” Weber asked.

“What do you think?” Muehlberg asked. “Yes. I'm not I'm not a complete animal. I have a conscience. I have, I have remorse. I have guilt. I wouldn’t be sitting here, talking to you all afternoon if I didn’t...

“Thinking back where my mind was, mentally and physically at this time period. I can honestly say I know something was off. Thank God it didn't last very long.”

Muehlberg paused, and looked into Weber’s body camera.

“For what it's worth, I'm sorry,” he said.

“It means a lot,” Weber told him.

“Yeah, I know,” he said. “Sorry don't make it right.”

To keep him talking, detectives let the conversation sometimes turn to other topics, like the 27 years he'd spent behind bars at that point.

“You learn not to judge people down here,” he said. “You just accept them for who they are at the moment.”

He told the detectives about two of his fellow inmates, whose crimes also shook the St. Louis area.

One is Charles Armentrout, who was released in prison in August 1994 after serving time for armed robberies. After his release, only his 81-year-old grandmother, Inez Notter, would let him move in with her.

In March 1995, he killed her after she refused to give him money to buy drugs.

“He killed his grandmother with a baseball bat,” Muehlberg said.

Another inmate he has come to know is Emory Futo.

“He killed his mother and father and two brothers in South St. Louis,” Muehlberg told the detectives, who recalled Futo’s 1991 crime.

Muehlberg also talked about the case that got him locked up for life, too.

That victim’s body was found in a makeshift coffin Muehlberg made for him in his basement.

“There was no smoking gun,” Muehlberg said. “The man was found in my house. That doesn't mean I killed him…There were things in my case that I’m here on that I’ll take to my grave.”

He said he was relieved after coming clean.

“Maybe I can do some easier time now that it's over and I don’t have to worry about you all coming down,” he said to the detectives.

“Yeah, you cleared the air,” Harvey said.

“Got a load off my chest,” Muehlberg said. “Now I can go back and think of what I'm going to have for supper tonight…

“It’s definitely one of the saddest days in my life, but also one of the best. I've lived for this one. Now I don't have to run inside me anymore from it because the truth is out here. No more pretending.”

Three weeks later, Weber returned, this time with Maryland Heights Detective Chris McNamara. In a letter to Weber, Muehlberg talked about a fifth victim he claims he left near a car wash once called Ram Jet along Natural Bridge in Berkeley.

But police have not been able to confirm this victim ever existed. They haven’t found any police reports matching Muehlberg’s description of the crime, or a body ever being found there.

Muehlberg insists he left her in a barrel outside a car wash.

Detectives fear the barrel could have been taken to a trash dump, without anyone ever knowing a body was inside.

“I remember taking her there in my van and leaving her there after I washed my truck,” he said.

“In the days or moments after them passing, just pick any one of them in your memory, what were your thought processes?” McNamara asked.

“Undoubtedly a whole bunch of different fear, nervousness, restlessness, I mean, what kind of emotions does a person have when they realize what they've done is totally wrong?” Muehlberg said.

He told them other prostitutes survived encounters with him.

“One or two went to my house and I took them back to where they were when I met him and nothing happened to them,” he said.

Later, he continued: “I didn't plan all this out before I picked them up.”

By their last visit on Sept. 29, 2022, word about Muehlberg’s past had spread through the prison.

He was no longer a killer, but a serial killer.

“A couple of the inmates came down knocking on my door like, ‘You're on TV,’ and I went, ‘Okay’ so when I got it turned on, it was like, ‘Whoa. Everybody knows now.’”

“So then, how are you mentally?” Weber asked.

“Better than I was the first time I met you,” he said. “And not near as good as I hope I will be someday.”

“Do you remember it being broadcast and paying attention to the news? And were you concerned?” McNamara asked.

“Yeah, undoubtedly was concerned, but as far as making a concerted effort to watch everything, I read the paper all the time. I knew they were going to be found eventually, and waiting for the knock on the door after they were found, like you said, with DNA or fingerprints or whatever, you would trace it back to me.”

Muehlberg told them none of the victims fought him.

One asked to be untied, but he couldn’t remember which one.

“I said, ‘No, it'll come later,’ or something to that degree,” he recalled, pausing once again. “Boy, some of this hurts…

“I can't imagine what these families have been going through for 32 years, for a lifetime.”

They talked about Muehlberg’s life, too.

“In college, you got your degree in psychology,” Weber said.

“Yeah, the study of the human behavior and the human mind, and look where I stand,” Muehlberg said. “I must have missed the course of doing right.”

He told detectives he was born just south of the Bevo Mill neighborhood, and moved to north St. Louis County as a toddler. He said his father was once the mayor of Bellefontaine Neighbors.

His father was also transferred to Cape Girardeau and then Kansas during his adolescence. He finished high school in Salina, Kansas.

He joined the Marines in the late 1960s and got married for the first time in 1970.

He said he was convicted of a robbery in 1972 and served 32 months in prison. He came back to the St. Louis area and graduated from Missouri Central Methodist in 1977, hoping to teach children with learning disabilities.

He married again in the 1980s and lived with his second wife in the home in Belridge where the murders happened.

He told detectives he soon returned to a life of crime, working for some of St. Louis’s most notorious mob families including the Trupianos and Leisures, helping them traffic marijuana while working for a refrigeration company.

He told detectives he had three children, two sons and a daughter. He was estranged from all of his children. One of his sons overdosed, and his daughter died from a kidney disorder as news of his identity as a serial killer was just beginning to break.

His only remaining son is a police officer out-of-state, who declined to be interviewed for this story.

“I know the suffering I went through, knowing April was not in the best of health and her demise,” Muehlberg said of his daughter. “I can’t imagine what these families are going through for the last 32 years, for a lifetime.”

He said his mind sometimes drifts to how differently his life could have been.

“I've lived down here going on a little over 27 years,” he said. “You don't fully or I don't accept it, but you deal with it on a daily basis. There's no alternative when you're doing life without. I mean, yeah, there's thoughts and dreams about what it could have been, what it should have been.”

He tried to assure detectives his motive for talking to them was pure.

“I'm not out to hurt anybody,” he said. “I don't want to cause any more grief in this world or in my life or anybody's life.”

He hoped his confession could do some good for families struggling with addiction – with no regard for what families like Robyn’s had already done to help their loved ones, or the sleepless nights her mother said she had worrying about her daughter.

“I'm sure there's families out there that, certain similarities they have,” Muehlberg said. “They've got a child or a loved one involved in this kind of career, prostitution, drug addiction.

“This may help them say, ‘Hey, you all better focus on this (expletive), because look what happened back here.’ You know, you get frustrated, you kick people out of your lives. Maybe they'll take an extra step to help them knowing that this kind of behavior does happen.”

Robyn’s mother said it has taken her a lifetime to realize her daughter’s struggle with addiction was not her fault, and her choices at the time of her murder were not because her family didn’t care about her.

Muehlberg went on to appear only via video during all of the hearings that followed – another heartache for Robyn's mother.

“When I faced him in court, he never said a word, about anything, even when I said ‘I forgive you, but only because my faith tells me I have to,’” Kuehnle recalled.

She remains unmoved by the sorrow Muehlberg talked about during his confessions.

“He thinks he's somebody, he's nothing but a monster,” she said. “I'm thankful to the good Lord that he did allow me to live long enough to know who it was.”

And, she says, he can keep his apologies.