A woman and her brother plotted the slaying of her soldier husband a week after his homecoming from the Persian Gulf war so they could collect on his life insurance, investigators were quoted Wednesday as saying.

Toni Cato Riggs, 21, and Michael Cato, 19, were charged Tuesday with murder in the shooting March 18 of Army Spc. Anthony Riggs on a Detroit street.Riggs initially was thought to have been slain in a robbery, and the case focused attention on how random violence can make the nation's streets as dangerous as a war zone.

Police Chief Stanley Knox refused to give a motive for the slaying. But homicide Inspector Gerald Stewart said the weapon had been traced to Cato and Mrs. Riggs, and the crime "had absolutely nothing to do with random street violence."

The Detroit Free Press, citing investigators it did not identify, said the pair wanted to cash in on Riggs' life insurance, which included a $50,000 military policy and a private policy purchased just before he left for Saudi Arabia.

Another newspaper reported Mrs. Riggs had recruited her brother to help with the slaying.

"Toni told Michael, `I'll take care of you for the rest of your life,' " an unidentified police officer told The Detroit News.

Mrs. Riggs and Cato were being held without bond Tuesday. Cato was arraigned Tuesday. Mrs. Riggs' arraignment was set for Wednesday.

Riggs, 22, was shot five times outside the home of his wife's aunt while helping his wife move.