Medical Examiner confirms missing Massachusetts woman was fatally injured in shooting as suspect ordered held without bail

TYNGSBOROUGH – Middlesex District Attorney Marian Ryan and Tyngsborough Chief of Police Shaun Woods have confirmed that Shawn Sullivan, 40 of Tyngsborough, was arraigned Tuesday in Lowell District Court on charges of murder, assault and battery with a dangerous weapon causing serious bodily injury and improper disposal of human remains in connection with the alleged shooting of a woman, now confirmed to be Jill Kloppenburg, 47, who had been reported missing to Tewksbury Police in February 2025.

The Office of the Chief Medical Examiner has identified the woman whose remains were found buried under the garage floor of the defendant’s home as Kloppenburg.  The preliminary findings also suggest that Ms. Kloppenburg sustained a gunshot wound.

On March 10, 2026,  the Nashua, NH, Police Department received a call regarding a possible homicide. The reporting party told police that his friend, a man named Shawn Sullivan, had allegedly told him that he had killed a woman named “Jill” at this home in or around January 2025, and that he had allegedly shot her and buried her under the floor in the garage of the Audrey Avenue home in Tyngsborough where he was living.

On March 15, detectives from the Tyngsborough Police Department, Tewksbury Police Department, and Massachusetts State Police executed a search warrant on the Audrey Avenue home and recovered the body of Jill Kloppenburg.

Shawn Sullivan was ordered held without bail.  The next scheduled date in this case is April 17, 2026.

The prosecutor assigned to this case is Ceara Mahoney.