'Your children are not safe'

ROCKVILLE, Md. -- Hours after a bus driver was killed in a shooting that appeared to be the work of the Washington-area sniper, police revealed Tuesday they had received a message over the weekend warning: "Your children are not safe anywhere at any time."\nThe chilling message apparently was discovered by police outside a Virginia steakhouse where the sniper critically wounded a man Saturday night.\nMontgomery County Police Chief Charles Moose said the warning came in the form of a "postscript."\nHe also said police "will be responding soon" to the latest message. He did not take any questions from the media.\nOn Monday, police asked the shooter to call them, saying investigators had received a message too muddled to be understood.\nEarly Tuesday, bus driver Conrad Johnson, 35, was fatally wounded as he prepared for his morning bus route in nearby Aspen Hill, the suburban Washington community where the shootings began Oct. 2.\nIn all, 12 people have been shot by the sniper in Maryland, Virginia and Washington, D.C.; three were critically wounded.\nJohnson, a father of two, was shot as he stood at the top of the steps of the bus shortly before 6 a.m. He died later at a hospital.\nMoose has now used four briefings to communicate directly with the person believed to be the sniper.\nA senior law enforcement official speaking on condition of anonymity said Tuesday a letter found near the scene of Saturday night's shooting suggested the killer wants several million dollars.\nTwo other law enforcement sources said the letter also contained information that police interpreted to be a vague threat to children. One of the sources, who also spoke on condition of anonymity, said the letter was "lengthy."\nSchools in the Richmond area, near Saturday's shooting, remained closed a second day Tuesday.\nImmediately after Tuesday's shooting, police put a widespread dragnet into place, clogging traffic on Connecticut Avenue, one of the main arteries into Washington, just as the morning commute began.\nThe shooting happened near an apartment building and wooded area along Connecticut Avenue. The bus was parked at a staging area where drivers get ready for their morning runs, state police spokesman Cpl. Rob Moroney said. He didn't know if anyone else was on the bus.\nAgents for the federal Bureau of Alcohol, Tobacco and Firearms combed the crime scene. A police dog searched near a basketball court in a park, and police helicopters flew over the scene.