Missing woman believed to have been found dead underneath garage floor after tipster called cops: DA

Inset: Jill Kloppenburg (FBI). Background: Audrey Avenue in Tyngsborough, Massachusetts, where Kloppenburg was found dead under a garage (Google Maps).

Authorities in Massachusetts say they have recovered a body they believe is a woman who has been missing for over a year. The body was found underneath a garage floor after the suspect allegedly admitted to a friend he committed a murder.

Shawn Sullivan, 40, is facing murder and other charges, Middlesex County District Attorney Marian Ryan told reporters at a press conference on Monday. Authorities are referring to the victim as "Jane Doe" until the remains — discovered in a shallow grave under a garage in Tyngsborough — are identified, but Ryan indicated that investigators believe they belong to 43-year-old Jill Kloppenburg, who disappeared in January 2025.

Kloppenburg was last seen on Jan. 2, 2025, leaving her home in the 700 block of Broadway in Lowell. Activity on her cellphone went dark nearly two weeks later. She was reported missing on Feb. 26, 2025.

On March 10 of this year, a friend of Sullivan's contacted the Nashua Police Department in New Hampshire to say Sullivan had admitted to killing a woman named Jill around January 2025, Ryan said at Monday's press conference.

Using missing persons databases, cops determined Sullivan was likely talking about Kloppenburg after they learned the two were friends. Investigators on Sunday searched a home on Audrey Avenue in Tyngsborough where Sullivan previously lived. Ground-penetrating radar indicated there was something buried under a two-car garage at the home, Ryan said.

Authorities discovered a body underneath the garage after carefully digging through a "large patch area" that was roughly 5 feet long and 3 feet wide, according to Ryan. The victim had been wrapped in plastic, Ryan said.

A medical examiner is working on positively identifying the body as belonging to Kloppenburg as well as a cause and manner of death, Ryan said. In addition to the Jane Doe murder charge, Sullivan is charged with assault and battery with a dangerous weapon causing serious bodily injury and improper disposal of human remains.

He's slated to be arraigned on Tuesday.

Friends previously told local Fox affiliate WFXT that they contacted cops after they could not get hold of Kloppenburg.

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"We're very concerned because she hasn't checked in. No matter what is going on in her life, she has always checked in with her friends," Ann Matlosz told the TV station.

Her uncle, Steven Kloppenburg, wrote on Facebook that cops notified him Sunday evening about finding the remains. He said his niece had a drug addiction problem and had the propensity to associate with "violent men."

"Though we were not particularly close, I find myself walking around since with eyes watery, on the edge of tears, for her loss, for what could have been," he wrote. "There will be a resolution."