In life, Sean Patrick Conroy's gentle nature endeared him to plenty of people, from the everyday customers at the Starbucks he managed in Center City to the old folks in his South Philly neighborhood.

But a number of people who never knew Conroy spoke and acted out yesterday, saddened and disturbed by the fatal beating he suffered Wednesday at the hands of a pack of teens on a subway platform near City Hall.

Exhibitors and other people who attended the Interphex convention - a trade show for pharmaceutical engineers and manufacturers - at the Convention Center this week decided yesterday to donate tips at a ballroom happy hour to Conroy's family.

They ended raising more than $800, said Cristina Poulos, an Interphex spokeswoman.

"A lot of our exhibitors had stayed at the Marriott where his Starbucks was, so they were upset when they heard what happened," Poulos said. "They wanted to do something nice for his family."

Conroy, 36, was headed to the Starbucks he managed at the Philadelphia Marriott Downtown, at 12th and Market streets, shortly before 3 p.m. on Wednesday.

He had just finished visiting with his fiancee - they got engaged on Easter Sunday - when five teens snuck up behind him in an underground SEPTA platform near 13th and Market streets.

Police officials said one of the teens punched Conroy in the back of the head. The force of the blow dropped him to the ground.

The young predators - four of whom were Simon Gratz High School students - commenced with a merciless beating, kicking and punching Conroy, causing him to have a fatal asthma attack, according to the medical examiner's office.

A SEPTA police sergeant who was on foot patrol on the opposite side of the tracks tried unsuccessfully to revive Conroy, police said.

The teens didn't bother robbing Conroy. Investigators determined that the attack had been a random, pointless explosion of violence.

Only one of the attackers - identified by police at Kinta Stanton, 16, a 10th-grader at Simon Gratz - has been arrested. He's facing murder charges and has been charged as an adult.

"It's beyond tragic. It's very senseless that this ignorant behavior could yield such tragic results,"said Chad Dion Lassiter, a youth-violence expert and adjunct professor at the University of Pennsylvania's School of Social Policy and Practice.

Lassiter, who provides violence-prevention training in local schools, said the attacks underscored a need for parents, schools and community members to seriously invest in the lives of children and teen who may be troubled.

"It's something we have to be committed to do and look at it from a mental-health perspective. Something is missing here. There's a lack of moral imperative within the young person," Lassiter said.

"There's a hopelessness, despair, hurt and pain that they're not able to express in manageable actions."

Lassiter said the teens won't realize the magnitude of their actions "until they're sitting in court, and a judge says you're being tried as an adult. They'll never get that moment back, and that family will never get that young man [Conroy] back."

Jennifer Edwards, a 20-year SEPTA cashier who works at the Fern Rock subway station, said she was saddened to hear of Conroy's death but not totally surprised.

"I've seen kids - young kids - attack people on trains for no reason at all," Edwards said. "I try to help people the best I can because I don't want anyone to get hurt." *