A 15-year-old Utah boy was arrested in connection with killing his two younger adopted brothers, who were aged 4 and 10. He apparently stabbed to death in their home while their mother was out at a musical recital, authorities said on Thursday, as reported by CNN. The unidentified teenager is being held at the Farmington Bay Youth Detention Center, as of Friday afternoon

A fifteen-year-old is in juvenile detention after being questioned for the deaths of his two brothers.

"It appears they did from a knife like wound," Sheriff Todd Richardson said. He added that the the 15-year old fled the home but police found him shortly after midnight late Thursday.

Two knives were believed to have been used in the crime, and were also recovered from the home. "As time goes on, I think it will be released as to why he did what he did," Richardson added.

A neighbor said that the two brothers who were killed were adopted, and the 15-year-old was his parents' biological son.

"You could tell there was a sibling rivalry between the biological son and the adopted boys," the neighbor told ABC4.com. "But I never imagined it could go this far."