The suspects are her boyfriend 16-year-old Anthony Lee and his brother Diante Coakley. They're charged with first degree murder. Both are from south suburban Dolton, which is where the Eva Casara was found.
Casara was shot to death on Christmas Day.
Police say a drug-related robbery was involved but will not elaborate.
"We are looking for one more subject," said Dolton Police Chief John Franklin. "I am not going to name him at this time because we have not as of yet obtained an arrest warrant for him we will be obtaining one this weekend and at that time he will be named."
Lee and Coakley are due in bond court Sunday. As for Casara's child, the baby was delivered prematurely.
A prayer vigil Saturday night attracted dozens of supporters.
Friends, neighbors and village officials came out in support of the teenager's family and of baby Lailani. Born at just 1-pound, 5-ounces, the infant is still struggling for life.
"She's hanging in there. She's a fighter. She's going to continue to fight," said Jennifer Ross.