Andrew K. Ruotolo Jr., who as Union County Prosecutor in New Jersey created a special task force to wage war against car theft in Newark, died on Thursday at his home in Westfield, N.J. He was 42.

The cause was cancer, according to his sister, Diane Webber.

Mr. Ruotolo, who was appointed County Prosecutor in 1991 by Gov. Jim Florio, also established the Union County Human Relations Commission to fight bias and hate crimes.

He formed the county’s first full-time Domestic Violence Unit, which included a protocol for dealing with rape victims, and the Union County Child Advocacy Center as a safe haven for child-abuse victims.

The Essex-Union County Auto Theft Task Force, which he started in 1993, made hundreds of arrests for stolen vehicles, leading to a 20 percent reduction in car thefts in the Newark area, according to the prosecutor’s staff.

Mr. Ruotolo, who was recently elected first vice president of the New Jersey Prosecutors Association, graduated from Amherst College in 1974 and Fordham University Law School in 1978. He was an assistant United States Attorney for New Jersey from 1981 to 1984, working in the criminal division.

He is survived by his wife, Mary Picaro Ruotolo; two daughters, Lyndsay and Jayne; a son, Andrew; his mother, Claire M. Vollmerhausen, and stepfather, Dr. Joseph W. Vollmerhausen, of Summit, N.J., and three sisters, Denise Ruotolo of Plainfield, N.J., Cynthia Sherwin of Cos Cob, Conn., and Mrs. Webber of Waverly, Pa.