How two friends helped crack a 39-year-old cold case involving a missing teenager from Chelmsford

The recent discovery of an old car in the Concord River is helping solve the mystery of a Chelmsford teen who went missing in 1982.

Checking on a TowFish Edge Tech 4125 for a rub test is Hans Hug of Sonar Search & Recovery at his two-car garage in Exeter, N.H. where his boat is along with the equipment that he used to find the submerged car in the Concord River that belonged to Judy Chartier, a Chelmsford teen who went missing in 1982.David L. Ryan/Globe Staff

When Hans Hug and Bruce Stebbins began searching along the bottom of the Concord River in August, they weren’t sure what they’d find.

“We had no idea,” said Hug.

Hug, 67, of Exeter, N.H., owns Sonar Search & Recovery, a business that specializes in underwater search and recovery operations. Stebbins lives in Billerica and has a remotely operated vehicle (known as an ROV). Together, on Aug. 21 the pair set out on the river on a boat with the hopes of finding the car that was once driven by Judy Chartier, a 17-year-old Chelmsford resident who went missing in 1982.

Judy Chartier held a photograph of her missing daughter, also named Judy Chartier. Tom Landers/Globe Staff/file

Using side scan sonar equipment made by EdgeTech, a company based in West Wareham, they were able to detect several potential targets to check out.

Hug described the technology, which uses sound to create three-dimensional images of objects underwater, as “ultrasound on steroids.”

Working independently, Hug and Stebbins scanned a 2½-mile stretch of the Concord River, from Lowell into Billerica.

Hug dropped a device known as a towfish down into the water, and they towed it behind the boat while Hug watched the images of submerged objects appear on his laptop. They did this for “the complete width of the river,” said Hug.

“I’m watching in real time everything the towfish goes over,” he said. “In fact, we found the car that day.”

One of the images they saw at the bottom of the Concord River would later turn out to be the 1972 Dodge Dart Swinger that Chartier was driving on June 5, 1982, the date she disappeared. Friends said they last saw the 17-year-old around 2 a.m. leaving a party in Billerica.

Hug said the car first appeared as a “rectangular anomaly” about 30 feet from the embankment of the river.

At that time, “I could not say positively it was a car,” he said.

This view from Hans Hug's laptop shows an example of what a submerged vehicle looks like underwater from Hug's sonar. (This is not Judy Chartier's Dodge, it's a different vehicle.)David L. Ryan/Globe Staff

Hug and Stebbins met in 2020 and became fast friends due to their shared interest in underwater exploration.

Stebbins was familiar with the Chartier case, and had a hunch that her car might have disappeared into water near the party in Billerica where she was last seen alive.

Hug said Stebbins later mentioned their mission to a Billerica police sergeant, who in turn informed Chelmsford police. Hug said on Oct. 1 he and Stebbins met with a Chelmsford police detective and explained what they were looking for, and the police gave them the green light to continue their search.

They then returned to the Concord River to get a closer look at their submerged targets. Using Stebbins’s ROV, which Hug describes as a “swimming robot,” they were able to positively identify one of their targets as a 1970s Dodge.

The first thing they saw was the round headlights.

“The minute we knew we had a car, we were really excited,” said Hug. “That’s a classic 1970s headlight.”

Upon further inspection, they could see the word “Dodge” embossed on the hubcaps. Then they saw other aspects of the design matched the description of a 1970s Dodge Dart.

“This car was in really rough shape,” said Hug. “But it said Dodge on the hubcaps. We knew we had a car, we knew we had a Dodge Dart. We looked at each other in astonishment, and were like, ‘No way!’”

Hug, an experienced scuba diver, then returned to the river and went into the water to get a closer look at the vehicle himself.

“The visibility was anywhere to zero to three feet,” he said. “Absolutely brutal.”

Hug said there was milfoil, an invasive type of aquatic plant, that was about four feet long growing in the back seat of the Dodge.

“The car itself was a mess,” said Hug.

Hug was extremely careful not to disturb anything underwater, in order to preserve any evidence from what could be a decades-old crime scene.

Hug said the location where the car was found was not far from the party that Chartier attended when she vanished in 1982.

Hug said he and Stebbins informed the State Police of their findings, “and the rest is history.”

“It was a bittersweet find,” Hug said. “We experienced major excitement … mixed with sadness. Because we thought, ‘Yes it’s probably Judy’s.”

On Nov. 2, Middlesex District Attorney Marian Ryan announced that the 1972 Dodge Dart Swinger was recovered and confirmed to be Chartier’s. During a subsequent search of the same area, police divers were able to recover human remains and personal items.

Ryan thanked Stebbins and Hug for their efforts, which helped crack a case that had stymied local law enforcement for decades.

“As we remain focused on uncharged cases in Middlesex County, we are thinking creatively about both traditional law enforcement tools and non-traditional partnerships,” Ryan said in a statement. “In this case we are extremely grateful for the work of Hans and Bruce who helped us to locate Judy Chartier and her car after nearly four decades.”

Hans Hug of Sonar Search & Recovery at his two car garage in Exeter, N.H. where his boat is along with the equipment that he used to find the submerged car in the Concord River that belonged to Judy Chartier, a Chelmsford teen who went missing in 1982. David L. Ryan/Globe Staff