Wilmington's police chief says a new gunshot-detection technology is helping officers make arrests. The city used a federal grant to install the ShotSpotter system in November. Acoustic sensors around a 3-square-mile area detect gunshots and immediately relay the information to police. Chief Ralph Evangelous is urging the city council to continue ShotSpotter once the federal funding runs out next year. It would cost about $120,000 dollars. Officials in other cities where the system has been proposed have objected to the cost in a time of tight budgets. Evangelous disagrees.