Justin Bieber, Ashton Kutcher SWATTER -- 12 YEARS OLD!!!

The juvenile who was arrested for phoning in prank 911 calls -- claiming there was gun violence at the homes of Justin Bieber and Ashton Kutcher -- is only 12 years old ... TMZ has learned.

Sources connected to the boy tell TMZ ... he lives in California with his mother. He refuses to go to school and sits at his computer day and night, communicating with other hackers. We're told he is antisocial, preferring the keyboard to personal contact.

Our sources say Children's Services has been to the boy's apartment multiple times, trying to stabilize the situation, to no avail. We're told the mother has virtually checked out. We're told the family is "incredibly dysfunctional."

Our sources say the boy is smart, but by no means a Zuckerberg-esque genius. Still, he was able to evade cops for months.

We're told law enforcement is sympathetic and steps are afoot to remove the child from the home and place him in a stable foster environment. We're also told authorities are inclined to get the boy counseling rather than mete out punishment -- i.e., place him on probation and if he completes his counseling program all charges will be dismissed.

It's pretty remarkable ... a 12 year old concocted incredible fake scenarios to fool cops ... telling them gun-toting Russian thugs had held people in Ashton's house hostage.