Authorities in Massachusetts say they have uncovered human remains buried beneath a garage floor in a grim discovery that may finally solve the disappearance of a woman missing for more than a year.

Investigators believe the body belongs to 43-year-old Jill Kloppenburg, who vanished in early 2025.

The remains were found buried in a shallow grave beneath a two-car garage in Tyngsborough after a friend of the prime suspect alerted police to a shocking confession.

Shawn Sullivan, 40, has now been charged with murder and several additional offenses, Middlesex County District Attorney Marian Ryan announced during a press conference Monday.

For now, investigators are officially referring to the victim as “Jane Doe” until forensic experts can positively confirm the identity of the remains.

But authorities say all signs point to Kloppenburg.

The discovery came after a dramatic break in the case earlier this month.

On March 10, a friend of Sullivan’s contacted the Nashua Police Department in neighboring New Hampshire and reported that Sullivan had confessed to killing a woman named Jill around January 2025.

Detectives began digging into the tip and quickly found a possible match.

Through missing persons databases, investigators learned Sullivan had known Kloppenburg, who had disappeared from Lowell around the same time he allegedly described.

Kloppenburg was last seen on Jan. 2, 2025, leaving her home on Broadway in Lowell.

Her cellphone remained active for nearly two weeks after she vanished before suddenly going silent.

Friends eventually reported her missing on Feb. 26, 2025, when they realized something was seriously wrong.

“We’re very concerned because she hasn’t checked in,” friend Ann Matlosz told local television station WFXT at the time.

“No matter what is going on in her life, she has always checked in with her friends.”

For more than a year, the trail appeared to have gone cold.

Then investigators obtained a search warrant for a property on Audrey Avenue in Tyngsborough where Sullivan had previously lived.

Using ground-penetrating radar, authorities detected an unusual disturbance beneath the concrete floor of the home’s two-car garage.

Investigators carefully dug through what prosecutors described as a “large patch area” measuring roughly five feet long and three feet wide.

Beneath the garage floor, they uncovered a shallow grave.

Inside was a body wrapped in plastic.

The remains were transported to the medical examiner’s office, where specialists are now working to confirm the identity and determine how the victim died.

While that process continues, prosecutors have already filed serious charges against Sullivan.

In addition to murder, he is accused of assault and battery with a dangerous weapon causing serious bodily injury and improper disposal of human remains.

He is expected to be arraigned in court Tuesday.

For Kloppenburg’s family, the grim discovery brings both heartbreak and a measure of long-awaited answers.

Her uncle, Steven Kloppenburg, shared an emotional message on Facebook after learning that authorities had discovered the remains.

He acknowledged that his niece struggled with addiction and sometimes found herself in dangerous situations.

But the news of her death still cut deeply.

“Though we were not particularly close, I find myself walking around since with eyes watery, on the edge of tears,” he wrote.

“For her loss, for what could have been.”

As investigators work to confirm the victim’s identity, prosecutors say the case may finally bring resolution to a disappearance that haunted friends and family for more than a year.