Several recent violent crimes by youths, including the vicious beating death of a Chicago honor student by a mob of teenagers, have sparked a new look at urban youth violence. Despite a steep overall drop in youth crime in recent years, researchers say many urban areas continue to be plagued by homicide and other violence involving young offenders. Some experts say tougher sentencing laws and a greater focus on parental responsibility are the best ways to fight the violence, while others argue for more federal money for social programs and anti-violence efforts. In some cities, collaborative approaches involving police, educators, community leaders and neighborhood groups are aimed at pressing youths to forsake violence while offering them a path toward redemption. Meanwhile, two competing proposals are being considered on Capitol Hill, and major foundations are funding programs to help youths in trouble.