WASHINGTON -- The case of the missing savings bond may have just gotten easier to solve.

The government announced yesterday that it has greatly expanded from 200,000 to more than 4 million the number of bonds that can be searched to see if they match up with the original bond holder's Social Security number.

It is all part of the government's effort to encourage the owners of some 33 million matured savings bonds worth more than $13.5 billion to redeem their holdings.

Under the program, people who think that they own a bond, but have misplaced the records of their ownership can visit the Web site -- www.publicdebt.treas.gov -- and click on the "Treasury Hunt" section under savings bonds and follow the instructions.

If the program detects a possible match, the bond holder is provided information on how to follow up to claim the bond.

"With the expansion of the database, bond owners or their heirs will be able to more easily determine if there are bonds that have been lost or mislaid," Treasury's Bureau of Public Debt said in announcing the program.

Series E bonds that were sold from May 1941 through November 1965 earned interest for 40 years. Bonds sold from December 1965 up to the present earn interest for 30 years.

The government began requiring Social Security numbers on all bonds sold beginning in 1974. But officials said that hundreds of thousands of bonds issued before then also include Social Security numbers.

The $13.5 billion in unclaimed savings bonds that have stopped earning interest are part of a total of $205 billion in savings bonds currently being held by the public.