An athlete. The funny guy. Not the type of person who made enemies.

That's how friends and classmates of Brian Joseph McCloskey described the 18-year-old Virginia Tech freshman who died Thursday afternoon from injuries sustained in a violent Saturday incident that remains shrouded in mystery.

Blacksburg police found McCloskey about 2 a.m. lying near a bike path in sight of Pheasant Run Crossing Townhomes, where he had earlier attended a birthday party.

He was bloody and had head and neck trauma. Soon after, he was flown to Carilion Roanoke Memorial Hospital and placed on a ventilator.

After McCloskey's death, Blacksburg Police spokesman Lt. Bruce Bradbery said the agency has identified "persons of interest" in the investigation and is following up on several leads.

But so far, police have not determined what led to McCloskey's death.

"Somebody somewhere knows what happened," Bradbery said. "They were there. And it is time for them to step up. His parents deserve an explanation."

Earlier in the week, police investigators outlined tire tracks that led from the townhouse complex across the bike trail and out onto nearby Givens Lane.

Bradbery said an autopsy to be performed today may help police determine if McCloskey was hit by a car or beaten.

"It's not one thing that makes it difficult to determine," Bradbery said, referring to the investigation. "If you find somebody and they are hurt real bad and there is a bloody baseball bat next to them, you can put two and two together. We don't have that."

As news of McCloskey's death spread through campus Thursday, friends struggled to deal with his passing.

McCloskey, whose older sister also attended Virginia Tech, is from Olney, Md.

Ryan Burnsky has known him since seventh grade. They played lacrosse together at Sherwood High School. They came to Tech together this year.

Burnsky said McCloskey was a class clown.

"We had the same English class in 11th grade," he said. "Our teacher was real hot. Right out of college. Every day he would ask her for her number. I think by the end of the year he did get it."

Burnsky said he will miss his hometown friend.

"It's a major tragedy," he said. "He's been a big part of my life. It's going to be different without him around."

At Tech's Thomas Hall, where McCloskey lived, he had a group of friends who would go out together on the weekends.

One of them, 19-year-old Fred Finch, said McCloskey was not the kind of person to get into fights.

Finch was not out with McCloskey on Friday night and can't imagine what happened to his friend.

Finch said the incident does not make him afraid for his own safety, but said he is not going to go out alone at night.

"It could easily happen to anyone," he said.