CAMDEN, Maine — A horror movie based on a screenplay written by best-selling writer Tess Gerritsen of Camden has been filming locally since the beginning of the month.

The film is being directed by Gerritsen’s son, Josh, and is being produced by Mariah Klapatch, who grew up and went to school in Camden.

Filming of “Island Zero” began March 2 and continued through Saturday, March 26, with one more day to be scheduled later, according to Klapatch, who hopes to have the movie released in theaters by the end of 2017.

Klapatch and Josh Gerritsen have known each other since they were in the second grade in Camden. Now, about 25 years later, they’ve come together to film “Island Zero” in Camden and surrounding communities.

“We were going for a swim at Megunticook Lake, and Josh said he and his mom wanted to know if I wanted to produce a movie,” Klapatch recalled about a conversation she had with him during the summer of 2014.

Tess Gerritsen completed writing the screenplay in early 2015.

Josh Gerritsen has done freelance video and photography assignments since 2004.

This is the first feature film produced by Klapatch, who studied film and television at New York University.

Klapatch said the movie is set on a remote island that has lost power and communications with the outside world after the ferry from the mainland fails to arrive. People begin dying off in gruesome and mysterious ways as a core group of residents begin to find clues to what is behind the acts.

A sea monster plays a role in the movie with the theme rooted in climate change and the impact humans have on the environment.

The film is a modified-low budget one at between $300,000 and $350,000.

Actors in the film include Laila Robbins, who has appeared in many movies, including as the wife of Steve Martin’s character in the 1987 movie “Planes, Trains and Automobiles,” and on television, including Showtime series “Homeland.”

Other actors in the film are Adam Wade McLaughlin, Teri Reeves and Matthew Wilkas.

Klapatch said one of the core goals of the production team was to employ and cast as many Maine people as possible. About 80 percent of the crew and cast of 50 are from Maine.

Klapatch, who lives in Los Angeles, said she hopes to return to Camden and is confident the state can be a place where feature films can be made.

Filming for “Island Zero” was done at 10 sites. In addition to filming at a home at 24 Thomas St. in Camden, crews shot scenes on Islesboro, including at Durkee General Store, and at Rockport Harbor, Camden Harbor, the Swan House bed and breakfast in Camden, and at multiple homes in Camden and Rockport.

There will be an initial screening of the movie at the end of the year for family, friends and people who worked on the movie, according to Klapatch. She also said Thursday she wants to showcase the film at film festivals in early 2017 with a theater release by the end of 2017.

There will be one additional day of filming later, when the dilapidated house at 24 Thomas St. in Camden is expected to be burned for one of the final scenes.

Klapatch and Camden fire Chief Chris Farley have asked the Select Board for permission to use the house for training purposes with the culmination being the burning of the structure.

Farley said non-wood items in the house will be removed, and anything that can be recycled will be. He said the owner is in contact with Habitat for Humanity, which may be able to use some of the material.

The Select Board will consider the filmmaker’s request at its April 5 meeting.