Hedy Lamarr, a sultry, raven-haired actress known for making an international splash while swimming and sprinting naked in the 1933 film "Ecstasy" and as the title femme fatal of 1949's "Samson and Delilah," was found dead Jan. 19 at her home in Casselberry, Fla., about 10 miles north of Orlando. She was believed to be 86.

The Seminole County sheriff's office is investigating the death, but authorities do not believe it to be suspicious, said spokesman Steve Olson.

Born in Vienna, Ms. Lamarr started her movie career in bit parts before her notorious 10-minute scene in the Czech film in which she cuckolds her husband.

The role in "Ecstasy," in which a horse gallops away with her clothes while she's bathing, made her a sensation despite attempts by her then-husband, Austrian arms merchant Fritz Mandl, to buy all the film prints before their distribution.

Mandl was unsuccessful, and "Ecstasy" became a cult favorite for later generations of cineasts who viewed it as a curiosity, sensual early art film and simple titillation.

Billed as "the world's most beautiful woman," Ms. Lamarr arrived in Hollywood in 1938 and portrayed European women of mystery for the next two decades.

Born Hedwig Eva Maria Kiesler, Ms. Lamarr was rechristened after 1920s film siren Barbara La Marr by Metro-Goldwyn-Mayer studio chief Louis B. Mayer. She became a U.S. citizen in 1953.

Her career in the United States is notable for a few minor classics, including "Algiers" in 1938, with Charles Boyer as a hunted thief who invites her into the Casbah, and "Tortilla Flat" in 1942, with Spencer Tracy and John Garfield in a script based on a John Steinbeck novel.

During the 1940s, she also appeared in "Boom Town" with Tracy and Clark Gable, "H.M. Pulham Esq." with Robert Young and "Experiment Perilous" with George Brent.

In all, Ms. Lamarr made more than 25 films that often depended on her voluptuous figure more than a demanding dramatic flair, among them "White Cargo" in 1942, in which she played native girl Tondelayo opposite Clark Gable, and "My Favorite Spy" in 1951, in which she was Bob Hope's beautiful foil. Her biggest American hit was opposite Victor Mature in a Cecil B. DeMille biblical epic, "Samson and Delilah."

Although she hoped for a career with wider emotional range, Ms. Lamarr took her career in stride as she saw her roles largely evaporate by the late 1950s. "Any girl can be glamorous," she once said. "All you have to do is stand still and look stupid."

Besides her film career, Ms. Lamarr's life wavered between alleged petty crimes and the invention of a visionary communications device. Two shoplifting charges, in 1966 and 1991, received widespread publicity, but the actress was exonerated on both occasions.

Her lesser-known achievement was helping to develop a device that made radio communications jam-proof using rapidly changing frequencies.

Sitting at a piano one day in 1942 with composer George Antheil, the ardently anti-Nazi Ms. Lamarr was following his lead on a series of notes when it occurred to her -- based on the knowledge she developed from her arms merchant first husband -- that a similar concept could block the enemy from jamming radio-controlled weapons.

At the time, her main contribution to the war cause was cheesecake pinups for overseas servicemen. After the original patent expired in the early 1960s, however, it was adopted by the military and, later, communications industries as a method of security precautions for their systems.

She remained a recluse for much of her life after her film career expired, with the exception of a few public rows. After her autobiography, "Ecstasy and Me: My Life as a Woman," appeared in 1966, she unsuccessfully sued her ghostwriters because of the portrayal of her love life in a manner she viewed as "fictional, false, vulgar, scandalous, libelous and obscene."

Ms. Lamarr's life had so many dimensions that she is too complicated to dismiss her as a brainless beauty during Hollywood's heyday, said Jeanine Basinger, the Wesleyan University film studies department chairwoman and author of "A Woman's View: How Hollywood Spoke to Women, 1930 to 1960."

"She herself created her own legend," Basinger said. "She was the last of a movie star type in which we'll never really know what her story was."

Her six marriages ended in divorce. Her husbands included writer-producer Gene Markey, actor John Loder, with whom she appeared in "Dishonored Lady" in 1947, and Texas oilman W. Howard Lee.

Survivors include a son and daughter from her marriage to Loder and an adopted son.