A 15-year-old may have killed his two siblings, according to a Utah police report out this week.

The teenager has been taken into custody by police and is being held in juvenile detention.

The boy, whose name is not being publicly released by police, is believed to be responsible for the deaths of his two younger brothers, who were aged just 4 and 10 years old, according to ABC News.

The bodies of the two younger siblings were found last week on Wednesday by their mother. The victims had fatal knife wounds on their bodies.

It is believed that the 15 year old committed the crime before fleeing the scene. However, police launched a search for the boy, initially believing that he may have also been a victim, however, he was eventually found shortly after midnight, and after an assessment of his condition he was arrested and taken into custody.

Police have confirmed that the boy had knife wounds as well, but reports are claiming that the boy's injuries were consistent with those possible when the victims may have tried to fight him off.

Authorities have confirmed that the 15 year old was a biological son of the mother, where as the two murdered victims were her adopted sons.

The family also consists of three other siblings – all of whom were not around at the time of the killings. Of the six children, four were reportedly adopted, and two others were biological children.

Various reports have claimed that sibling rivalry was one of the main factors thought to be behind the killings, and had been an issue in the family in the past.

The killings have stunned local communities near Salt Lake City.