Roberto Clemente is as popular in death as he was in life.

Nearly 30 years after he died in a plane crash while en route to deliver supplies to earthquake victims in Nicaragua, Clemente memorabilia ranks among the most popular sports collectibles.

His sudden death on a humanitarian mission, not to mention that he collected his 3,000th hit in his last regular-season game, contribute to his idol status among Hispanics. But nearly two thirds of the "Clemente" signatures on the market today may be forgeries, according to a leading authenticator of items autographed by athletes.

There are just too many signatures in circulation of player who passed away before card shows became popular, according to officials at James Spence Autographs, a signature verification service.

Complicating these factors is the thought that Clemente didn't sign much of his own mail throughout the late 1960s and early '70s. Clubhouse attendants John Holihan and Field Dorcey signed most of Clemente's mail, according to James Spence.

Clemente's 1955 Topps rookie card in near mint condition is worth $2,000, according to Beckett.com. Clemente's signature on an official major-league baseball is worth as much as $4,000.

"I don't think there are enough Hispanic collectors like me to drive up the price of Clemente collectibles," said Felix Velez Jr., a 42-year-old Clemente collector and a native of Puerto Rico who now lives in Fords, N.J. "There are just a lot of baseball fans that find Clemente intriguing."

Velez has more than 200 Clemente collectibles, including a game-used bat and many autographs, which he stores in the family room of his basement. His daughter, who plays soccer in high school, wears No. 21 in Clemente's memory.

Indeed, more of Clemente's collectibles hit the market each year.

"I ship a lot of items to Hispanics in Puerto Rico, Texas and California," said Chuck Thomas, a memorabilia dealer in Pittsburgh who sells everything from root beer cans bearing Clemente's likeness to sawdust from his game-used bats. "To them, he's a god."

Darren Rovell, who covers sports business for ESPN.com, can be reached at darren.rovell@espnpub.com.