CHICAGO (CBS) -- Authorities are looking more at self-defense as a motive in a South Chicago Heights case in which a 14-year-boy is accused of stabbing and killing his 16-year-old brother.

Investigators tell WBBM Newsradio they are leaning away from murder charges -- at least at this point -- against the unnamed youth, whom police say used a large kitchen knife to stab his brother, Larry Miles.

South Chicago Heights Police Chief William Joyce says the 14-year-old is not believed to be a threat to anyone and has been released to the custody of his grandfather.

Chief Joyce would not confirm what a source tells WBBM -- that the stabbing may have been a case of self-defense and that  if any charges are filed, they would be less serious than murder charges.