2004 marks the bicentennial of the Lewis and Clark expeditions to the West, and a U.S. senator wants to solve the mystery behind Meriwether Lewis' death in time for the celebration.

Sen. Frank Murkowski, ranking member of the Senate Energy and Natural Resources Committee, which oversees the Interior Department and the Park Service, has asked the National Park Service to allow Lewis' body to be exhumed to determine if the famous explorer died by murder or suicide.

"Meriwether Lewis deserves better than to be in the middle of a mystery whose solution is within reach," Murkowski said. "World-class scientists and world-class technology are standing by, ready to give his family and history the answers. All that stands in the way is world-class bureaucracy."

But the Park Service has denied a previous request, saying it has no foundation for digging up Park Service graves unless they are threatened by park development and natural forces.

Lewis was buried near Hohenwald, Tenn., on national park ground, in October 1809 at age 35.

At the time of his death, he was at a frontier outpost off the Natchez Trace south of Nashville. Historical records show an innkeeper said he found Lewis fatally wounded after he heard "two pistols fire off" at 3 a.m.

As the story goes, Lewis asked to be put out of his misery, and said, "I am no coward but I am so strong, so hard to die." He died a few hours later.

While the rumor spread that he killed himself, some historians believe he may have been murdered during a robbery.

More than 160 of Lewis' relatives say they want the exhumation.

"We want the mystery cleared up," said Jane Henley, a Lewis relation, speaking for the family. "The mystery continually overshadows his contribution to American history."

George Washington University professor James Starrs, who exhumed outlaw Jesse James, is willing to conduct the post-mortem tests to end speculation about his death.

"The strategy is in the political arena now," said Starrs, a professor of law and forensic sciences who was denied the request in 1998.

Murkowski, R-Alaska, said the Park Service's concerns that the exhumation on park land will set a precedent are "groundless."

"The Park Service simply has not convinced me that there is a reason why they should be denied. I am asking the Park Service to provide me with additional materials about their denial," he said.

The bicentennial celebration will kick off next year at Monticello, near Lewis' birthplace and home of Thomas Jefferson, who set the two-year expedition's wheels in motion.

The Associated Press contributed to this report.