NEW YORK - Spider-Man, X-Men, Iron Man and The Incredible Hulk can save the world from evil through superhuman feats, but it took a federal judge Thursday to decide who legally owns the rights to their lucrative characters.

U.S. District Judge Colleen McMahon ruled that they and other Marvel Worldwide Inc. superheroes will remain the property of the company, despite claims by heirs to the artist who played a key role in creating them that they are entitled to the copyrights.

The Manhattan judge cited statements made by artist Jack Kirby before his 1994 death to support her finding that his creations must remain Marvel's property.

She noted that he said in a 1986 affidavit that he did his work at a time when it was common practice that vested ownership of his creations belonged to the company that paid him to draw. She said he also signed a written agreement in the spring of 1972, well after the creation of the characters, admitting that he was not entitled to retain ownership of the work.

Marvel filed a federal lawsuit in January 2010 seeking to invalidate 45 notices sent by Kirby's heirs to try to terminate Marvel's copyrights, effective on dates ranging from 2014 through 2019. The comics were published between 1958 and 1963. Those at issue in the case included The Fantastic Four, The Incredible Hulk, The Mighty Thor, Spider-Man, Iron Man, The X-Men, The Avengers, Ant-Man, Nick Fury and The Rawhide Kid.

Marvel had said the work was done "for hire," a legal term that would render the heirs' claims invalid. McMahon said the plain language of contracts she reviewed made it clear that all of Kirby's work for publications owned by Marvel was work for hire. She said the 1909 copyright law that applies to the case presumed that Marvel was considered the author and owner of Kirby's creations because the characters were made at Marvel's expense.

McMahon said the case had parallels to one involving a book about Gen. Dwight D. Eisenhower's account of World War II. A federal appeals court concluded in that case that the book was created at the expense of the publisher and thus was a work for hire.

"Like Eisenhower, Kirby took on none of the risks of the success of the many comic books he helped produce. His contribution to the enterprise was plainly critical, but Marvel, not he, bore the risk of its failure," she wrote.

A lawyer for the Kirby family did not immediately return a telephone call for comment. Kirby is survived by his wife and their four children.

In a statement, The Walt Disney Co., which purchased Marvel in 2009, said: "We are pleased that in this case, the judge has confirmed Marvel's ownership."