President Bush signed into law a bipartisan plan to give the Contras non-military aid, even as State Department officials looked into human rights allegations that could block the $49.8 million package.

The administration was trying to determine the veracity of a report Tuesday in The Washington Post that the Nicaraguan rebels failed to expel a commander who was convicted of covering up a murder. The story said the rebels ignored a warning by a top State Department official that they were required to take such action in order to remain eligible for the new U.S. aid.The new aid, the product of a March 24 bipartisan agreement between the administration and Congress, calls for cutoff of the money if there are human rights abuses by the Contras.

The State Department said the Contras' own military tribunal on March 23 expelled six Contra members for human rights violations, including the rebels' head of intelligence, known as Commandante Mack.

But The Post, citing rebel sources, reported that Mack was still working at Contra headquarters despite his conviction and expulsion.

"His attendance at any official resistance function would be forbidden under the expulsion order," said a State Department official, who spoke on condition of anonymity.

The official said that Commandante Mack and a regional commander known as Commandante Nolan both had appealed their convictions to the Contra directorate.

Deputy Assistant Secretary of State Chris Arcos confirmed Tuesday that he had made clear to the rebels during a meeting within the last three weeks that they were expected to remove the violators from their ranks.

"Legally we would have the basis," to halt the aid if they did not, Arcos said.