PORTLAND, Maine — Pop artist Robert Indiana, best known for his 1960s "LOVE" series, has died at his island home off the coast of Maine. He was 89.

Indiana died on Saturday from respiratory failure at his Victorian home in a converted Odd Fellows hall, a fraternal order lodge, where he had lived for years on Vinalhaven Island, said James Brannan, his attorney.

Friends had expressed concern for his well-being because the reclusive artist had not been heard from for some time. A lawsuit filed in New York City the day before his death suggested he was purposefully isolated by his caretakers.

Brannan declined to comment on the situation.

The artist's "LOVE" sculpture, in which the "L'' and a leaning "O'' sit atop the "V'' and the "E," is instantly recognizable worldwide. But he has created other works as well, and fashioned a "HOPE" design, similar to "LOVE," in honor of former President Barack Obama.

"In some ways he was perhaps seen as the proverbial one-hit wonder because 'LOVE' was so immensely iconic and immensely huge in pop culture. For better or for worse, it overshadowed some of his other contributions," said Dan Mills, the director at Bates College Museum of Art in Lewiston, Maine.

In his later years, he was known for living an increasingly reclusive life 15 miles off the mainland on Vinalhaven, where he moved in 1978.