A 17-year-old has been charged with murder in the death of a paddleboarder who went missing in Maine, authorities said on Friday.

Maine State Police said on Thursday that a teenage boy, who has not been publicly named, was taken into custody the night before in Union. 

The teen was charged with one count of murder, the state attorney general’s office said on Friday. 

Sunshine Stewart, 48, was found dead during a search of Crawford Pond on July 3 in the town of Union, Maine State Police said last week in a statement. The Office of Chief Medical Examiner in Augusta said the cause of death was strangulation and blunt force trauma.

The arrest was the “result of relentless investigative work” and the teen was taken to Long Creek Youth Development Center in South Portland, police said.  

Kathy Lunt, the owner of Mic Mac campground near Crawford Pond, told CBS affiliate WGME that Stewart was a seasonal resident there. Stewart had gone on a solo paddleboarding trip and never returned, according to WGME. Police said her body was found under “unusual circumstances.”

Stewart lived about 21 miles from the pond, which is a popular summer destination about 15 miles from the scenic coastal areas of the state’s midcoast region.

The killing shocked and scared the community. Friends of Stewart have posted online testimonials remembering her as fiercely independent and always up for a challenge, including outdoor adventures and building projects. Over the years, she worked in many roles, including as a fisherman and bartender, friends said.

Stewart renovated her home in Tenants Harbor, a neighborhood in St. George, said Bruce Twyon, a friend who knew Stewart from her time living in the Virgin Islands. That spoke to her self-motivation and spirit of “getting things done and enjoying life every day,” he said.

“She was such a sweet person and very strong and independent, and took care of a lot of people,” Twyon said.

The pond, in the 2,400-resident town of Union, is about 600 acres and does not have public access. It is available for a variety of uses, including boating and fishing. The 100 Acre Island preserve in the center of the pond is a wooded island reachable by canoe, kayak or paddleboard from a nearby campground.

 The pond has numerous nooks and narrow areas, so it’s possible there were other boaters on the water at the time of the killing who were unaware someone was in danger.

Police said Thursday that the investigation was still active and they were seeking information from anyone who may have seen Stewart paddleboarding on July 2 on Crawford Pond.