Woman and Boyfriend Plot “Revenge Killing” After Her Ex Dates Sister: "Kill Them Both"

On October 13, 2021, a disturbing crime occurred in a peaceful Denver, Colorado suburb.

That day, Witnesses heard five gunshots pierce the air at lunchtime, and several ran out of their Longmont homes to find their mail carrier, 33-year-old Jason Schaefer, laying in a pool of blood next to their mailboxes and his mail truck. He’d been shot at close range as he tried to deliver letters.

“That kind of act is personal. It’s a revenge killing of some sort,” Dr. Richard Lettieri, forensic neuropsychologist, said on A Plan To Kill, airing Sundays at 7/6c on Oxygen. “The perpetrator was so angry they wanted to look him in the eyes and be seen before that person pulled the trigger.”

Neighbors described the suspect to police as a man with a hoodie and blue mask. Several Ring cameras caught the figure shooting Schaefer, as well as the suspect running through the neighborhood. Many also saw the suspect before the shooting happened.

“[One] saw kind of this shadowy figure standing across the street, almost like they were just waiting,” Josh Burke, Longmont Police Department detective, said on A Plan To Kill. “Whoever the person was, they specifically had waited for Jason to be by himself before approaching from across the street. That was a strong indicator to us that this was planned.”

Police started their investigation by focusing on Jason Schaefer’s personal life. He and his ex-girlfriend, Devan Schreiner, met while both working for the U.S. Postal Service in Colorado. Their son was born in 2015.

“Jason wanted a family, so when Devan got pregnant, he was very happy, and we were happy for them,” said Lori Hebert, Schaefer’s mother, on A Plan To Kill.

But the couple started to have trouble after the birth of their son.

“Their values were not the same. She did not want to work. She felt she didn’t have to work, being a mother. But, you need two paychecks. Their relationship started to deteriorate, and they broke up,” Hebert said. “Jason tried to get along and co-parent together, and that wasn’t working very well. So, Jason wound up getting a lawyer to set up a parenting plan.”

On Oct. 11, 2021, just two days before he was gunned down, Jason Schaefer filed for increased custody of his son.

“In looking at her phone it was clear that she was served with that paperwork,” said Boulder County prosecutor Alison Brand on A Plan To Kill. “[She] was aware that he was seeking increased custody and time with their shared child.”

Jason Schaefer’s mother shared with police another personal reason for Devan Schreiner to be angry with her ex-boyfriend.

“Just before the murder, Jason mentioned that his girlfriend, Rosa, was living with him,” Hebert said. “I didn’t think it was a good idea because Rosa was Devan’s younger sister. I told Jason, ‘You’ve opened up a bad can of worms here.’”

Despite the fact that Schreiner had a new boyfriend, AJ Ritchie, those close to her confirmed she was upset.

“They learned that Devan Schreiner was not happy about Jason Schaefer dating her sister,” Brand said. “She had vented to multiple friends, including AJ Ritchie, about her anger at the situation including saying things such as, ‘They have a new family now. My son. Jason. And my sister.’”

Police were able to connect Schreiner to the murder scene when a black Nissan Rogue was captured on surveillance cameras driving around the neighborhood at the time of the shooting. Schreiner drove a black Nissan Rogue.

Schreiner was supposed to be delivering mail 30 miles north in Loveland, Colorado as her ex-boyfriend was slayed but when police pulled GPS data from her mail scanner, they discovered it was stalled in the same place for an hour at the time Schaefer was killed. She claimed to be at AJ Ritchie’s house eating lunch when her scanner was stalled.

But Ritchie’s story didn’t match Schreiner’s. Surveillance video showed he was at Hooters eating lunch with friends at the time of the shooting.

Although Ritchie couldn’t be the shooter, police discovered he was still involved. A search of his cell phone location data showed his path matched that of Jason Schaefer in the hours before Schaefer’s death.

“In watching that, it’s almost scary. AJ was on top of Jason almost the entire mail route,” Burke said. “It looked like AJ had been waiting for Jason’s mail truck to leave the post office that morning and then AJ followed him all around for two to three hours.”

Police found another important piece of evidence on Ritchie’s phone.

“There was this saved Snapchat photo that AJ Ritchie had screenshotted and saved to his phone,” Brand said. “That showed an individual taking a selfie picture in a bathroom wearing a very similar outfit that the shooter had worn on October 13, 2021.”

That individual was Devan Schreiner.

As police analyzed both AJ Ritchie and Devan Schreiner’s phone data, it became clear they’d been plotting Jason Schaefer’s slaying since finding out he was dating Schreiner’s sister.

Ritchie sent Schreiner a text about “ending Rosa and Jason” on July 8, 2021. Another text he sent to her read, “U could jst kill them both.”

“These messages had been sent months prior to the shooting,” Burke said. “Well before Jason had filed for the additional parenting time.”

Cell phone data showed Ritchie and Schreiner were on a call for nearly three hours the morning of the murder.

“We believe he was coordinating with Devan,” Burke said. “He was sending information back to Devan about where Jason could be found on the mail route … AJ’s the lookout for Devan.”

Eventually, AJ Ritchie confessed to the plan to kill.

“There was extensive thought that went into this murder. Devan’s gonna plant her cell phone and her [mail] tracker up at AJ’s house,” Burke explained. “And as soon as she knows that last location for Jason, she has a good idea where he’s going to be when she gets down to Longmont from Loveland.”

Both AJ Ritchie and Devan Schreiner were found guilty of first-degree murder and sentenced to life in prison without the possibility of parole.

Watch all-new episodes of A Plan To Kill on Sundays at 7/6c on Oxygen.