FBI agents investigating the murders of two members of a Baltimore family whose bodies were discovered at Fort Meade have discovered a man they believe was an eyewitness to one of the slayings, according to an affidavit filed today in U.S. District Court here.

According to the affidavit, the alleged eyewitness, Michael Anthony Spratt, 21, said Kenneth Howard Neal, charged with murder in one of the slayings, picked him up in a car at 3 p.m. last Saturday. Spratt said Donzella Peters, three children and George Peters Jr., 17, Donzella Peters' brother, were in the car.

Spratt said in the affidavit they headed from Baltimore to Annapolis and, while driving, Neal and Donzella Peters "had arguments" and Neal grabbed a knife wedged between the bucket seats of his car, reached over and stabbed George Peters, who was in the back seat.

Spratt said that when he was dropped off at a bus stop in Annapolis at 4 p.m. he believed that George Peters was dead, but the other four alive.

The bodies of George Peters and 3-year-old Dominick Peters, Donzella Peters' nephew, were found later Saturday at Fort Meade. Sherrill Peters, 2, Donzella Peters' niece, was found Sunday near Seneca in Montgomery County suffering from stab wounds. FBI agents continued today to search the Fort Meade and Annapolis areas for Donzella Peters and her 3-year-old daughter, Danielle Shoulders.

Neal is charged with murdering 3-year-old Dominick Peters.

He previously was charged with murder in the stabbing death of George Peters, but that charge was dismissed today in U.S. District Court here at the request of prosecutors. The prosecutors said they had learned from Spratt that Peters was killed outside Fort Meade, a federal property. They said the federal government therefore lacks jurisdiction.

Neal was arrested Sunday afternoon at his Baltimore home.

Assistant U.S. Attorney Herbert Better asked Magistrate Clarence Goetz today to continue to hold Neal without bond in Dominick Peters' death, saying the evidence detailed in the affidavit "is overwhelming" and Neal presents a danger to Donzella Peters and her daughter if they are still alive.

In addition, Better said that clothing that Donzella Peters and the others were taking to a laundromat when they disappeared "was found in the defendant's home."

Goetz did order Neal held without bond. He said he also will approve on Monday prosecutors' requests for blood samples from Neal and a mental examination of him unless his court-appointed denfense attorney's object.