A federal judge in Washington agreed to provide a new lawyer for William Eliu Martinez, who faces a mandatory minimum sentence of 10 years for helping to run what law enforcement authorities described as one of Central America's biggest cocaine smuggling rings. A jury convicted him in June of distribution of cocaine and conspiracy to import cocaine.

Martinez, 46, complained in a letter to the judge that his court-appointed attorney stopped speaking to him and failed to call character or defense witnesses during the trial. He said the attorney also failed to heed his request to file an appeal after the jury's guilty verdict. Additionally, he said, the Spanish-English interpreters made mistakes in translating a key portion of trial testimony.

"I feel that many of my constitutional rights have been violated," Martinez wrote in an Oct. 19 letter to visiting U.S. District Judge Michael M. Mihm, who presided over the trial. The case was tried at the federal courthouse in Washington because it involved drugs that were brought into the United States.

Martinez's attorney, Shawn Moore, an assistant federal public defender, and co-counsel Lara G. Quint sought permission to withdraw from the case in light of Martinez's allegations.

Mihm, who met privately with Martinez and the defense attorneys before granting the motion to withdraw, said during a hearing yesterday that he was reluctant to change lawyers between the trial and sentencing. Given the allegations, however, he said he felt he had no choice. He said he would confer with Chief U.S. District Judge Thomas F. Hogan on selecting a replacement defense attorney. No date was set for sentencing.

Moore declined to comment on the allegations.

Michael C. Mota, a Justice Department prosecutor, said during the hearing that Martinez had raised similar complaints during the trial but that Mihm had decided then against stopping the proceedings.

Martinez served as a congressman from the National Action Party in El Salvador from 1999 to 2002. He is confined to the D.C. jail, where another inmate helped him write the letter.

Martinez's family and friends have created a Web site, calling him "a good, honest and dedicated public official" who has been "wrongfully accused."

But prosecutors argued at his trial that he helped smuggled 36 tons of cocaine into the United States from 1998 to 2002 and used his position as a congressman to cover up the crimes.