UNION, Maine — Police in Maine are investigating the death of a paddleboarder near a campground in rural Maine as a homicide and asking the public for help finding the killer.

The body of Sunshine Stewart, 48, of Tenants Harbor, Maine, was found Thursday on Crawford Pond in Union. The manner of death was determined to be a homicide, though the cause of death is not being released to the public yet, Maine State Police said in a statement.

Police have asked that anyone who may have seen Stewart paddleboarding on July 2 between 6 p.m. and 9 p.m. near 100 Acre Island on Crawford Pond contact them. Maine State Police said in a Wednesday evening statement it remains “steadfast in our efforts to investigate” the killing.

Stewart lived about a half hour from the pond, which is a popular summer destination about 15 miles (24 kilometers) from the scenic coastal areas of the state’s midcoast region. Friends and family who gathered at Stewart’s home on Wednesday declined to comment.

Crawford Pond is located in the 2,400-resident town of Union, about 80 miles (129 kilometers) northeast of Portland, the largest city in the state. The area is popular with campers and daytrippers.

The pond is approximately 600 acres (243 hectares) 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 lake 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 have asked residents to remain aware of their surroundings and report suspicious behavior. Maine State Police said Wednesday they have been reviewing leads and tips and are sensitive to the way the killing has unnerved the community.

“The Maine State Police recognizes the fear and discomfort that this incident has brought to the town of Union and the Crawford Pond community,” the agency said in a statement that called on residents to “remain vigilant.”

Loved ones of Stewart, who was known as “Sunny” to friends, launched a GoFundMe page in her honor in the wake of her death. The page states that arrangements and memorial service dates were still being determined. The page had raised more than $19,000 by Wednesday.

“Today is a somber day for our family and friends. We’ve unexpectedly lost the light in our lives that was Sunny,” the page said.

The killing is a shock to the community, where family trips to the lake are a summertime staple, said Debbie Hilt, who lives in the area. Hilt said she knew Stewart as a child and knew her to be a regular user of the lake as an adult. Hilt described the island on the lake as a draw for campers looking for a quiet, secluded location.

“I’ve been on the lake since the early ’60s. I grew up down there since I was 8 years old,” she said. “I don’t even remember anything like this.”

Katharine Lunt, the owner of the nearby campground, which is called Mic Mac Cove Campground, said in a Facebook post that authorities have been using the campground to access the crime scene. The crime scene is not located on the campground itself, the post says.

Lunt said in the post that her business is not commenting on the investigation other than to say it is cooperating with authorities who are working the scene.

“The investigators have been here doing their job and we do not need the media distractions at this time,” the post says.