ROCKLAND, Me. — The artist Robert Indiana, who in his final years was the subject of a struggle over who represented him and controlled his work, left behind an estate worth an estimated $28 million, according to a court filing on Friday.

Mr. Indiana, best known for his “LOVE” sculpture and its many variants, died on May 19 at the age of 89 at his home on the island of Vinalhaven, Me. His will, filed on Friday in Knox County Probate Court, leaves most of his art and property to a nonprofit whose mission is to develop Mr. Indiana’s home into a museum featuring his works.

[Read the New York Times obituary of Robert Indiana.]

The will said the organization was to be run by Jamie Thomas, Mr. Indiana’s caretaker in his final years.

The day before Mr. Indiana died, Morgan Art Foundation, a company that says it has long held the rights to several of his best-known works, filed a federal lawsuit alleging that Mr. Thomas and a New York art publisher had isolated Mr. Indiana from the world and produced unauthorized or adulterated versions of his art.