LONG BRANCH, N.J. (CBSNewYork) — A devastated New Jersey family is demanding justice for their daughter who was murdered over the weekend.

Sources say the man behind bars for the crime was not in the United States legally.

The pain of losing a friend is impossibly unfair for the teens who are all barely halfway through high school. Even worse was when that friend was by all accounts as wonderful as Madison Wells.

“Honestly I’m taking it pretty hard right now,” friend Victor Lemus said.

“She was just this bright light that everybody needed in their life,” friend Joseph Escriba said.

Hundreds of Madison’s classmates and teachers from Long Branch High School gathered in grief to light candles and comfort her family, still reeling over the murder that took the beautiful young woman away.

“It’s tragic, tragic when you see a life, so full of life… Lovable and energetic, taken so quickly for reason,” teacher Yvette Rice said.

Family members say the 16-year-old was killed Saturday night at a relative’s house by a boy she was dating. Her father, Ed Wells, says Bryan Cordero Castro “stabbed her to death and ran like a coward.”

Police arrested Cordero Castro nearby three hours after the gruesome crime.

“She met this guy, puppy love I guess,” Ed said. “He was an illegal immigrant and I found out his age and I had a problem with it.”

Law enforcement sources tell CBS2 the 20-year-old Cordero Castro, of Guatemala, was not in the United States legally. Friends of the young couple say they never saw it coming.

“They were happy together. I’ve seen them hold hands… He was a family person, she was God’s gift,” friend Vinicius Silva said.

Cordero Castro will be in court early Thursday. Madison’s family is expecting a huge turnout when she’s laid to rest on Friday.