2 Students Slain as School Awaits N.Y. Mayor’s Visit : Crime: Schoolmate is apprehended in shootings tied to a grudge. Security had been heavy for Dinkins’ arrival.

A 15-year-old student shot and killed two schoolmates Wednesday in a high school swarming with security guards preparing for a visit from the mayor, police said.

Ian Moore, 17, and Tyrone Sinkler, 16, were shot point-blank in a second-floor hallway at violence-plagued Thomas Jefferson High School in the rough East New York neighborhood of Brooklyn.

The suspect went to school looking for them, then “walked right up to them without saying a word and shot them,” Deputy Inspector Patrick Carroll said.

Moore was hit in the head and Sinkler in the chest; they died soon after at a hospital.

Karen Yelzerton, 17, said Moore and another student had fought three months ago. The suspect apparently carried a grudge, authorities said.

“The guy told him yesterday he was going to get him today,” said Moore’s stepfather, Phanel Floizio. “But he didn’t believe it.”

The shooting occurred 90 minutes before Mayor David N. Dinkins arrived for a speech.

Board of Education spokesman Jim Vlasto said that under a rotation program, hand-held metal detectors are taken to Jefferson about once a week. He did not know when they were last used, but said they were not there Tuesday or Wednesday.

Vlasto said the school had 20 security guards Wednesday instead of the usual 13.

A school security guard apprehended the suspect. The district attorney’s office was considering charges and his name was not released.

Sinkler’s father, James Sinkler, said his son recently transferred to Jefferson because another student was shot in his last school, Westinghouse High School in Brooklyn.

“Every kid should be searched before they go to school and if they don’t want to be searched, don’t let them in. . . . School is like Vietnam,” the elder Sinkler said.

On Nov. 25, a 16-year-old Jefferson student was shot to death and a teacher was seriously wounded in a hallway. Police arrested a 14-year-old who said he was trying to help his brother in a dispute.

School authorities said the November shooting was the first time a student was killed inside a New York City school in more than a decade.

“The staff takes these things very hard,” said shop teacher Scott Peritz, who witnessed that one. “But the kids come in the day afterward and it’s old news. They’re a product of the environment.”

Board of Education President Carl McCall, among the officials consoling the victims’ families Wednesday at Brookdale Hospital, said Moore’s mother had been “concerned about his security. She was praying for him as he went off to school.”

The mayor arrived at the school’s auditorium after 3,000 students already had been addressed by Principal Carol Beck.

The mayor deplored violence and gun possession, and said students should concentrate on education.

“You’ve got to survive to get educated,” Dinkins told them. “You’ve got to eliminate the violence.

“For God’s sake, don’t let somebody with some grudge get you into difficulty and involved in violence.”