A 17-year-old Berkeley High student shot his best friend Saturday afternoon at his family’s apartment on Alcatraz Street, according to sources.

The boy and his friend had spent the day in Emeryville at a football game and were hanging around afterward, according to the grandmother of the boy who allegedly shot his friend. The gun went off and hit the other boy in the head. He was taken to the hospital where his injuries are life-threatening, according to Sgt. Mary Kusmiss of the Berkeley police department. She said the victim was in his “mid-teens.”

911 dispatch received a call about the shooting at 3:26 p.m., said Sgt. Kusmiss. The caller was male and was still at the apartment when police arrived, she said.

The 17-year-old was in police custody Saturday night, according to his grandmother. No charges have been filed.

Neighbors who saw the 17-year-old after the incident said he came out of the apartment complex with blood splattered on his shirt, shaking and crying.

His grandmother said she was surprised to learn that her grandson, who is a junior, had access to a gun. She thinks the shooting was an accident because her grandson would not have deliberately hurt his closest friend.

“If they were playing with the gun, I know it wasn’t intentional,” said said. “If it is an accident [he needs to] just tell the truth.”

Neighbors who live in the four-apartment complex described the 17-year-old as a nice kid.

“He’s a good boy,” said one 19-year-old neighbor who identified herself as Slim Bree. “They are cool neighbors. We all get along. It is just shocking that something like this happened.”

The grandmother, who said she has 20 grandchildren, said one of her grandsons died a few years ago after he was robbed of $20 and shot in the head. Another grandson died of a heart attack at 7. Her family has always stayed out of trouble, she said.

Frances Dinkelspiel, Berkeleyside and CItyside co-founder, is a journalist and author. Her first book, Towers of Gold: How One Jewish Immigrant Named Isaias Hellman Created California, published in November...