Remains buried under garage may belong to Jill Kloppenburg, Massachusetts woman missing since Jan. 2025

Human remains found buried under a Tyngsboro, Massachusetts man's garage may belong to Jill Kloppenburg, who has been missing for over a year, Middlesex District Attorney Marian Ryan said Monday.

Ryan said that the discovery came after a friend of 40-year-old Tyngsboro resident Shawn Sullivan called Nashua, New Hampshire police March 10 to report a possible murder.

The man told police that Sullivan said he had shot and killed a woman named Jill in January 2025, before burying her under his garage. Ryan said that Sullivan lives in the home with his family. 

Police used a radar to determine that something was underneath the two-car garage on Audrey Avenue and began digging through the "large patched area." They discovered human remains in a plastic bag.

Investigators said that they are awaiting confirmation on the identity of the victim, but said that they were able to determine it is possibly missing 47-year-old woman Jill Kloppenburg from Lowell.

"They could tell me they were 100% positive the remains were hers though they still have to confirm it with DNA and an autopsy has to be done to try to determine a cause of death, she's been missing for 14 months and has probably been out there for the whole time," Kloppenburg's uncle Steven Kloppenburg said on Facebook.

Kloppenburg was reported missing in February 2025 by friends who lived in Tewksbury. They had not been in contact with her since November of 2024, according to Ryan. 

Sullivan and Kloppenburg were friends, according to investigators. 

"She had been in his home and that he had allegedly been with her around the time of her disappearance," Ryan said at a press conference. 

He is charged with the murder of Jane Doe until an identification can be made on the remains, assault and battery with a dangerous weapon to cause bodily harm, and improper disposal of human remains. He will be arraigned in Lowell District Court on Tuesday. 

Kloppenburg's family said that they can "now focus on justice and healing." 

"I really hope that the family gets peace," said neighbor Ella White.

"On behalf of the entire Tewksbury Police Department, we offer our sincere condolences to Jill's loved ones. Our thoughts are with her family and friends during this incredibly difficult time," Tewksbury Police Chief Ryan Colombus said in a statement.