The slow propagation leads to prolonged heating and might cause sterilizations of the soil or the killing of roots, seeds, and plant stems at the ground level.

Mr. Federici said Brooklyn Union Gas has no reason to believe the killings stemmed from anything other than senseless, random violence.

Stephen R. Lewis, who represented Officer DiGuglielmo, said the killing "stemmed from the victim's hitting his father with a baseball bat."

Whereas Louima's beating was a premeditated, unprovoked act of barbarism, Diallo's killing stemmed from street-crime patrols, where heavy suspicion of blacks is inevitable, if unlawful.

According to court records, the killing stemmed from a dispute with another gang, Korean Power, over who would extort protection money from a massage parlor, court records show.

He said he thought the killings stemmed from a feeling shared by many in the army that the Jesuits were helping the rebels.

In Brooklyn, where many killings stem from drug dealing and domestic disputes, investigators said that murders that arise from white-collar crime are uncommon.

The killing stemmed, in part, from a turf dispute, Mr. Christie said.

Investigators are trying to determine whether the killing stems from a shooting on Oct. 10 when a 33-year-old Mount Vernon man was shot in front of a New Rochelle nightclub.

And with each awakening, she wondered anew whether the killings really stemmed from a racial dispute, hoping against hope it wasn't so.