Cheryl Piechowicz, whose husband and sister were gunned down execution-style a few days before they were to testify for the federal government in a narcotics trial here, will undergo a government-sponsored change of identity for her own protection, federal officials said today.

Piechowicz and her 5-year-old daughter, Sherrie, have already left Baltimore and are living in an undisclosed place while documents giving them new identities are prepared by the government.

Sponsored by the witness protection program of the U.S. Marshals Service, the identities will include new names and Social Security numbers.

Under the volunteer program, Piechowicz and her daughter will live permanently elsewhere in the United States.

Piechowicz's husband, Scott, and her sister, Susan Kennedy, were slain April 28 when a man entered the suburban motel where they worked and fired several rounds from a machine gun at them. Both Scott Piechowicz and Kennedy were scheduled to testify in the heroin trial of Anthony Grandison, starting May 2.

Cheryl Piechowicz was also a key witness in the trial and ultimately testified against Grandison, who was convicted. Piechowicz has told reporters she believed the gunman intended to kill her. She was scheduled to work at the hotel with her husband on April 28, but Kennedy replaced her at the last moment, she said.

This week, FBI agents arrested two alleged associates of Grandison, Vernon Evans Jr. and Janet Patricia Moore, charging them with witness tampering and civil rights violations in the death of Scott Piechowicz.

Federal prosecutors named Evans as the triggerman in the slayings.