A 12-year-old boy has been arrested on suspicion of murdering his 8-year-old sister Leila Fowler. The unnamed boy was the same one who called to report the murder, telling the police that a stranger fatally stabbed his sister.

Last month, Leila and her brother were alone in their Valley Springs home in California when the boy reported to police that he had found an intruder in the house. The intruder fled and the boy found his sister, who was in another room from him, with severe injuries. He called his parents who then called 911.

Leila was stabbed 21 times, and was pronounced dead at the hospital.

Her brother described the man as 6-foot-tall with muscular build and long gray hair. A manhunt was held, with the authorities searching for the "armed and dangerous" suspect door to door, even sending divers to look for clues in reservoirs.

According to AP, several knives were recovered from the family's home to determine if one of them was used to kill the girl. A neighbour who told police that she saw a man flee the home recanted her story.

The police said the brother wasn't considered a suspect, although they acknowledged that they continued to talk to him because he was the last person with Leila.

But after 15 days of investigation, the Calaveras County Sheriff's Office has announced that they have arrested the brother late Saturday. He will be charged with homicide. His name is being withheld because he is a minor, and no new details of the investigation would be released.

"Citizens of Calaveras County, you can sleep a little better tonight," Sheriff Gary Kuntz told reporters on Saturday, assuring residents that there was no dangerous child murderer on the run.

Hundreds of California residents flocked to Leila's vigil three days after her murder. Several members of her family were also present, including her mother, Krystal Walters, who said, "I just want to thank the entire community, our family and friends for the overwhelming amount of support you've given my family. It will never be forgotten."