Tyngsboro man accused of killing woman and burying body under garage says it was "tragic accident"

Shawn Sullivan, a man accused of killing a woman and burying her body under the garage of his home in Tyngsboro, Massachusetts has been ordered held without bail. His attorney said Sullivan accidentally killed Jill Kloppenburg, then buried her after an "extreme amount of panic."

Sullivan, 40, was arraigned in Lowell District Court on charges of murder, assault and battery and improper disposal of human remains. 

In court on Tuesday, the prosecutor said that during a second conversation with police, Sullivan admitted he removed a gun from the safe in his bedroom and showed it to Kloppenburg. When he made a twitching motion, the gun went off.   

Kloppenburg was shot in the chest. The bullet went through her body and an exit wound was found on her back.  

Attorney says death was "tragic accident"

Sullivan's attorney Ryan Sullivan, who is not related to the defendant, argued that he should be charged with involuntary manslaughter, not murder. The attorney said Sullivan did not intend to kill Kloppenburg, but panicked after her death and decided to bury her.

"The government has all the authority to charge as high as they possibly can. But it looks to me like all of the evidence suggests this was a tragic accident followed by inexcusable panic," Ryan Sullivan said.

The prosecutor said that the remains found buried at Sullivan's home were confirmed to belong to Kloppenburg, who had been missing for more than a year.

Investigators said the break in the case came on Wednesday, March 10 when a friend of Sullivan's called police in Nashua, New Hampshire 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. Sullivan lived in the house with his family.

Jill Kloppenburg death investigation

Officers then searched Sullivan's home on Audrey Avenue and noticed that part of the floor in his two-car garage had been repatched. They started digging and later found human remains in a plastic bag.

Detectives used a missing person's database and connected the case to the 47-year-old Kloppenburg, who went missing in January 2025.

According to the prosecution, Sullivan left Kloppenburg in the bedroom for a day or two after her death, then moved her body to the garage. He dug a 3-foot by 5-foot hole, buried her, then attempted to conceal the hole.

Authorities said Kloppenburg and Sullivan knew each other, she had been in his home and that they were together at the time of her disappearance. But the extent of the relationship is not clear.

"She didn't deserve it"

Outside of court, friends of Kloppenburg were not buying Sullivan's defense.

"He dug a friggin' hole in his garage, you think he's sorry? No," one friend said.

"She didn't deserve it all, nobody does, nobody," added Kloppenburg's friend, Theresa Brink. "She's a human, she was a mother, friend, a sister a daughter."

Brink and others were emotional outside the courthouse, recalling the times they knocked on the Sullivans' door while they were searching for their then-missing friend.

"We went to that home so many times, I knocked on his door with the flyers we made," Cindy Crowley said.

A judge ordered Sullivan held without bail. He is next scheduled to appear in court on April 17.