Other teenagers filmed as boys beat Khaseen Morris, and did nothing as Khaseen lay bleeding.

The final bell rang Monday at Oceanside High School, and before long more than 50 teenagers had gathered in a strip mall parking lot a few blocks away.

One was Khaseen Morris, 16. He was told to show up. One day earlier, Morris was seen walking a girl home in their neighborhood on Long Island, in New York. And it was a problem: Her ex-boyfriend was looking for a fight, police said.

Now Morris was surrounded. A violent melee broke out as a group of six or seven assailants lunged at Morris and a couple of his friends. Other teenagers filmed as boys beat Morris, then did nothing as Morris lay bleeding on the pavement, fighting for his life from a stab wound to his chest.

The assailants all fled. The videos all circulated.

Morris died in the hospital hours later.

"Kids stood here and didn't help Khaseen," Nassau County Police Det. Lt. Stephen Fitzpatrick said Tuesday at a news conference. "They would rather video this event. They videoed his death instead of helping him."

On Wednesday, 18-year-old Tyler Flach was arrested and charged with second-degree murder in Morris's death, the Nassau County Police Department said in a statement.

The case is the latest example of a brutal beating captured on video and turned into entertainment on Snapchat and other social media platforms, leaving a digital footprint of a violent tragedy. Fitzpatrick spoke directly to the teenagers who filmed, admonishing them for standing idly with their cellphones as one of their peers died. The videos have helped police identify most of the assailants, Fitzpatrick said. But still, he said, there should never have been Snapchat videos of the high school junior's killing.

"I don't know what to make of it, my generation versus this generation," he said of the phenomenon. "This can't go on. Your friends are dying while you stand there and video it. That's egregious."

Fitzpatrick said arrests are imminent, but police are still seeking more information on other attackers, who are believed to be from multiple local high schools.

Friends, family and classmates gathered in the strip mall's lot for a vigil Tuesday night. In an interview with Newsday, Morris's older sisters described him as free-spirited and artistic, an aspiring photographer who liked to draw anime and write his own music. He dyed half his dreadlocks burnt orange, and rode his skateboard around the neighborhood blasting a mix of rap and punk music from his speakers. The family had just moved to Oceanside from neighboring Freeport, and Morris's sister, Keyanna Morris, said he finally felt like he fit in.

"When he came here," the 30-year-old told Newsday, "he was able to be his kind of different with no judgment and he loved it. The moment he stepped foot in Oceanside, everyone loved him."

But then came a fight over a girl - all because Morris walked her home. His sisters said the other boy began sending threatening messages before school that morning, leading to the fight later that day.

"Him being so nice, that one good deed that he did got him killed," another sister, 22-year-old Kedeemah Morris, told the New York Times.

In recent years, everything from fatal overdoses to wild fights in broad daylight have wound up on Snapchat and Facebook and YouTube. Last month, a 14-year-old died of an apparent drug overdose while other teens filmed his distress at a skate park in British Columbia and took pictures, saying, "Carson almost died LOL." In 2017, a man was beaten to death with a glass liquor bottle in the middle of rush hour in Chicago as people drove and walked by - or stopped to record a video, the Daily Beast reported. None intervened to help.

"This is the society we live in now, where things like this sometimes become the next viral video," a Chicago police officer told the Daily Beast at the time.

In Morris's case, eventually, the video made its way to his family. Keyanna Morris wept as she recalled watching her brother bleed out on the ground, Newsday reported.

"He was in so much pain," she said.