Human remains found beneath the concrete floor of a Tyngsboro garage are believed to be those of missing Lowell woman Jill Kloppenburg, Middlesex District Attorney Marian Ryan said Monday. Investigators cut into a patched section of the garage during a court-authorized search and discovered a bag containing human remains. Although authorities say the remains are believed to be Kloppenburg, they have not yet been formally identified, and the investigation remains very much active. Prosecutors said they intend to seek charges in connection with the case.
Tip and search warrant
According to Boston 25 News, the break in the case started with a phone call on March 10, when Nashua police heard from a friend who said a man identified as Shawn Sullivan had claimed he killed a woman and buried her under his garage floor. Tyngsboro police, Massachusetts State Police and Tewksbury officers then secured a search warrant for the home, where they noticed a roughly 5-foot-by-3-foot patch in the garage floor and brought in ground-penetrating radar, which flagged an anomaly beneath the concrete. After crews cut through the patch, the Office of the Chief Medical Examiner confirmed that human remains had been recovered inside a bag, although the DA emphasized that official identification has not yet been made.
Missing-person background
The FBI's ViCAP missing-person entry lists Kloppenburg as last seen leaving her residence at 735 Broadway St. in Lowell on Jan. 2, 2025, according to the FBI. That listing remains active as local and federal investigators work to piece together what happened to her.
Charges and what officials say
Middlesex District Attorney Marian Ryan said prosecutors will charge a Tyngsboro man with murder, assault and battery with a dangerous weapon causing serious bodily injury, and improper disposal of a body, according to Boston 25 News. The Chief Medical Examiner is still conducting testing to determine the cause of death and to complete a formal identification of the remains. Tyngsboro Police Chief Woods called the discovery a "tragic loss of life" and added that, based on what investigators know so far, the case does not appear to involve a random act of violence.
What investigators are asking
Authorities describe the probe as ongoing and say there is no known threat to the public at this time. The FBI's ViCAP page for Kloppenburg lists contact information for tips and urges anyone with information to reach out to local police or the FBI, according to the FBI. Officials say they expect to release additional details once forensic identification is complete and further investigative steps are taken.
