Eight teen-agers accused of stealing to get night club admission money were charged in the subway slaying of a Utah tourist who came to the aid of his mother when she was punched in the face, police said. Five were picked up for questioning at the Roseland Ballroom after the fatal attack Sunday night, Capt. Steve Davis said. The other three were arrested Monday. Killed was Brian Watkins, 22, of Provo, Utah. The former college tennis player was in town with his family for the U.S. Open tournament. He was stabbed once in the chest after intervening when his mother was punched. He collapsed on the subway platform at 53rd Street and Seventh Avenue after starting to chase the fleeing thieves, Davis said. ``Brian jumped in to help me when one of the muggers hit me in the face,'' Karen Watkins said. She was treated for a mouth cut. The slaying reinforced New York's image as a hotbed of urban crime. It was the 18th killing in the city's subways this year. In Watkins' hometown, one homicide was recorded for all of 1989, Provo police records secretary Bobbie Ferguson said. The Watkins family, tennis fans who have visited New York for the past five years to see the U.S. Open, had spent Sunday at the tournament and were on their way to dinner when they were attacked. Their hotel is near the subway station where Watkins was stabbed and the Central Park restaurant they were headed for is located just two subway stops away. Watkins was waiting for a northbound train with his father, Sherwin, his mother, his brother Todd and Todd's wife Michelle, when a group of young men approached, one carrying a knife, another wielding a box cutter. Sherwin Watkins' pants were slashed and thieves took a money clip containing about $200 and some credit cards. One punched Mrs. Watkins in the face. The brothers interceded and one of the men stabbed Watkins, police said. He died later at a nearby hospital. Watkins' father was treated for a leg cut. The dance club is less than a block from the subway station where Watkins was stabbed. Davis said ``most kids who get off at that stop are going to Roseland,'' and that it was ``logical'' to investigate there. Debbie Jaspering, a family friend, said she'd seen the Watkins family at the tennis tournament several days ago, before she returned to Provo. ``They were having a great time,'' Jaspering said. ``They were sitting with the family of Brad Pearce,'' a touring pro from Provo who lost in the first round of the Open. ``My sister and I had been nervous, you know, two women alone in the city,'' she said. ``And this happens to the Watkins, with three men there. It's crazy.'' Manhattan detective Chief Joseph DeMartino said police recovered several weapons, including a cardboard cutter and a folding ``butterfly knife'' believed to be the weapon used to kill Watkins. The motive of the crime was to get money for admission into the night club, DeMartino said. Arrested was Yull Garry Morales, 18, of Queens, who police said stabbed Watkins. Also arrested and booked for investigation of murder and robbery were: Johnnie Hincaipe, Anthony Andersen, Louis Fernando Montiero, Ricardo Lopez, Emiliano Fernandez, all of Queens; Pascual Carpenter, of Long Island and Ricardo Nova, address unknown. All are 18.