A Colorado federal prison employee has been charged as an accomplice in the recent murder of a postal worker allegedly gunned down by his ex-girlfriend while delivering mail on his daily route. 

Andrew Ritchie, 34, of Longmont, was taken into custody Tuesday at Englewood Federal Correctional Institution in Littleton, where he works, FOX 31 reported, citing an arrest affidavit released Wednesday. He was booked into Boulder County Jail on a charge of first-degree complicity to commit murder. 

His arrest came hours after Devan Schreiner, 26, appeared in court Tuesday where she was formally charged with first-degree murder in the shooting death of her 33-year-old ex-boyfriend Jason Schaefer on Oct. 13. A judge ordered her held without bond until her preliminary hearing on Jan. 10. 

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Schreiner and Schaefer shared two children and had been involved in a lengthy custody battle. Two days before the shooting, Schaefer had filed documents to have parenting time modified, the affidavit says. 

"I knew that she didn’t do this alone," Brandy Brackett, a U.S. Postal Service employee who has worked with Schaefer for many years, told FOX 31 following Ritchie’s arrest. "I knew there was somebody there supporting her in this decision. We really wanted him to be caught."

"I was extremely happy to know that the person that helped her with this is now somebody that’s going to be held accountable also," Brackett said. "That made me extremely happy."

Investigators believe Schreiner and Ritchie were involved in a romantic relationship. Ritchie initially insisted that the two were just longtime friends, the affidavit says, but later allegedly admitted to the romantic affair after Ritchie was heard in a voice message uncovered from Schreiner’s phone telling her that he loved her earlier the day of the shooting, KMGH-TV reported.

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Schreiner and Schaefer previously worked together at the Longmont Post Office, but Schreiner was fired two weeks before the shooting. She was also spotted entering the building without permission and going through Schaefer’s belongings but left before anyone confronted her, Longmont Daily Times-Call reported. Schreiner got a new job at as a U.S. postal carrier for the Loveland Post Office. 

Andrew Ritchie (left) was charged as an accomplice in connection to a murder allegedly carried out by Devan Schreiner (right).

Andrew Ritchie (left) was charged as an accomplice in connection to a murder allegedly carried out by Devan Schreiner (right). (Boulder County Jail )

Ritchie later admitted to police when he dropped Schreiner off at work that morning he told her "today is the day," and "I have everything I need." 

GPS from both of their phones showed them in the vicinity of Schaefer’s mail truck that day, and cameras from several houses in the neighborhood showed Ritchie’s vehicle following Schaefer along his delivery route. Ritchie allegedly told detectives he was on the phone with Schreiner multiple times before the shooting to try to convince her not to go through with it, claiming that he was following Schaefer in order to warn him. 

He said Schreiner later called to say she had gone through with killing her ex-boyfriend. Police uncovered 9 mm ammunition next to a 1911 handgun in the console of Ritchie’s Chevy Silverado, affidavit says. 

"Postal inspectors from across the nation converged into Colorado to support to the Longmont Police with this important investigation. Longmont Police personnel are skilled, experienced and capable of resolving investigations of this nature, and the U.S. Postal Inspection Service considers the safety of USPS employees to be the most critical element of our mission and has committed the full strength of our federal law enforcement resources to bring justice for Longmont letter carrier Jason Schaefer and his family," Ruth Mendonça, inspector in charge of the Denver Division of the U.S. Postal Inspection Service, said in a statement, according to KCNC.

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 "The arrest of the second suspect in Mr. Schaefer’s homicide demonstrates our collective commitment to leaving no stone unturned in this investigation and to pursue justice to the fullest extent of the law."