The 12-year-old who is accused of stabbing his 8-year-old sister to death last month is denying the charge against him. The boy, who is identified as Isaiah F. in court, may face imprisonment until his 23rd birthday if he is convicted of the murder.

The youngster pleaded not guilty to charges of second-degree murder Wednesday at Calaveras County juvenile court. His mother, father, and his father's fiancée were in court.

The boy only appeared in court for two minutes, according to the Stockton Record.

The murder of Leila Fowler in Valley Springs, Calif., had shocked the nation, and even more so after her brother was named the main suspect for the murder. His trial date is set for June 31.

Leila was stabbed multiple times on April 27 when she was home alone with her brother.

Isaiah had initially told police that he saw an intruder in the house that night. Police carried out a manhunt for the suspected intruder, but after a two-week investigation, charged the 12-year-old with Leila's murder.

"We got in believing our client was innocent, and as we stand here, that's what we believe," said Isaiah's lawyer Mark Reichel, according to KCRA. However, he did admit that his client had lied about the intruder but concluded that it didn't mean that he killed Leila. "We're still in the middle of our own personal investigation of the facts," Reichel said.

Isaiah is currently being held in a cell in a juvenile facility. He was reportedly suspended from school in January for bringing a Swiss Army knife, Reichel told Reuters.

The Fowler family have left their home where their daughter was killed.

Leila and Isaiah lived with their father and his fiancée at the home in Valley Springs.