The boy lives in the capital, Vilnius, while the girl lived in Altus. According to police spokeswoman Dalia Petrauskiene, the girl's half-nude body was found at a bus stop outside Vilnius on Sunday.
Lithuania is one of Facebook's fastest growing markets. It has approximately 710,000 users in a country with a total population of only 3.4 million. If found guilty of murder, the boy only faces a maximum 10-year sentence, perhaps because of his age.
Ironically, it appears that Petrauskiene, the aforementioned police spokeswoman, has her own Facebook account.