Police say Griffin was attacked while walking home.
After following hundreds of leads, 18-year-old Timothy Easely of Sauk Village, Griffin's former boyfriend, was charged in connection with the girl's murder and sexual assault.
Easely is scheduled to appear in court Wednesday morning.
From the very first moment that friends and family learned that she was missing, they say they suspected her former boyfriend was responsible. Police say Easley was their prime suspect from the beginning because he was the last person to be seen with her when she was alive.
Courtney Wilson, Griffin's god sister, said there is a sense of relief now that there was an arrest in the case.
"I'm real happy that they finally did it," she said. "Five months is not a long time, but to wait like this, it's forever."
Easley was charged with three counts of first-degree murder. Police say the two dated for a while and both attended Bloom Trail High School. But she broke it off two months before she was killed. Police the motive was that Easley wanted to get back together with her, and when she refused he became enraged.
"He met with Brashai and during the course of that meeting, Brashai was brutally sexually assaulted and subsequently murdered," said
Police say Easley denies any involvement, but they say DNA evidence and phone records prove their case and say Easley has a prior juvenile record of several sexual assaults.
Police said it was the toughest homicide case they have had in many years because of the young age of the victim and because Griffin was so well loved.