Two teenage brothers were home alone in their suburban neighborhood when an argument over loud music spiraled out of control, police said, leaving one brother dead from a knife to the chest and the other accused of killing him.

William Gorzynski, 15, was being held in juvenile custody on suspicion of second-degree murder in the Monday afternoon death of 14-year-old Matthew Gorzynski.

According to police in Coral Springs, about 45 miles north of Miami, Matthew was playing music on a home computer. William was watching television nearby and complained the volume was too loud. He told him to turn it down. Matthew refused. The two yelled at each other, then fought.

Then William went to the kitchen, grabbed a 7-inch knife and stabbed his brother in the upper left chest, Sgt. Joe McHugh said.

William called 911 soon after and told the dispatcher he had just stabbed his brother.

"It's actually a confession on tape," McHugh said. "He's actually describing what occurred. This was definitely not accidental."

McHugh said the tape won't be released publicly because it's considered evidence.

Gorzynski's attorney, Glenn Roderman, said William is in disbelief.

"I don't think he even believes it happened," Roderman told the South Florida Sun-Sentinel.

Roderman did not immediately respond to requests for comment from The Associated Press.

"It's something he can't even fathom," Roderman told the newspaper. "This is a very beautiful and wonderful family. They can't even believe it happened."

He said they "fought like every other brothers do, but they don't fight in an unusual way."

The Florida Department of Children and Families has had "prior involvement" with the family and was reviewing its investigation, but would not comment further, said spokeswoman Elisa Cramer.

According to the police report, officers responded and smelled an "overwhelming odor of marijuana" inside the home. The report said the younger boy was "lying on the floor of the bedroom near a stain of blood that soaked into the carpet."

The older brother "spontaneously uttered, 'It was an accident, is he going to be OK?"'

The boy told police "he accidentally stabbed Matthew and later placed the knife back into the knife block."

The 14-year-old died about an hour later at a nearby hospital.

Prosecutors said no decision has been made on whether the teen will be charged as a juvenile or adult, and no formal charges have been filed yet.

No one answered the door at the family's single-story home in a tidy, neatly groomed neighborhood on Wednesday. The boys lived there with their other brother, Timothy, 19, and their single father, Thomas.

"Don't come up on my property," a teenager yelled from the home's front yard.

Outside the home, a makeshift memorial formed of stuffed animals, candles and balloons left by neighbors and friends. William and Matthew were typical brothers, they said. They skateboarded together, rode bikes, played in the neighborhood and attended the same nearby high school.

A.J. Wood, 16, left his skateboard deck at the memorial. He wrote on the board: "Ride the sky, Matt. RIP."

"But it doesn't mean rest in peace," he said, crying, tears streaming down his face. "It means ride in peace, because you know, you never rest when you skate."

A.J.'s younger brother, 12-year-old Ken, stood by his side, sobbing.

"We skateboarded together, just hung out, had a good time," Ken Wood said, wiping tears from his cheeks. "I don't understand."

Neighbor Ann Dauria, 50, said the boys were just like any other teenage brothers and never caused any problems. Their father is an engineer raising his kids on his own, she said.

"It's like a father has lost two sons now," Dauria said, her voice cracking. "I fought with my brother, too. But years ago, we fought with our hands. Times have sure changed since I was growing up."