Government prosecutors yesterday revealed that a second witness has identified Bernard C. Welch as being in the same Northwest Washington neighborhood on the night Washington cardiologist Michael Halberstam was slain at his home on Battery Place.

Welch previously had been identified by Halberstam's widow, Elliot Jones, on the night of the slaying as he lay injured after being hit by Halberstam's car, which the dying doctor drove onto him.

In court papers filed by the U.S. Attorney's Office in D.C. Superior Court, prosecutors said that a second witness was able to pick Welch out of a police lineup and "links defendant Welch to offenses charged in the indictment."

It was not clear, however, what the second witness claimed to have seen. Welch was indicted on 11 charges, including first-degree murder, several burglaries, and a pistol violation. All the offenses occurred at Northwest Washington locations last Dec. 5.

The identity of the witness was not disclosed in the court papers. A witness who picked Welch out of a police lineup previously has been described by sources familiar with the case as being a woman and having been in the vicinity of Battery Place NW the night of the shooting. The existence of a second witness could be significant since Welch's attorney, Sol Z. Rosen, has challenged the validity of the identification of Welch made by Jones.

The U.S. Attorney's office also said in court papers that Linda Sue Hamilton, the woman with whom Welch had lived since 1976, gave police verbal and written permission to search Welch's car the night of the shooting. Police retrieved "a large amount of jewelry, silver and money in the trunk" of the car, the court documents show.

It was Hamilton who first told police of the "great deal of gold, silver, jewelry and money" located in Welch's Great Falls home in Fairfax County, according to the prosecutors. Hamilton, who is not a suspect in the case, gave police permission to search the house, the prosecutors said. Welch's trial is set for April 1.