Earlier this year, a judge dropped charges against Ardelean for a lack of evidence.
But on Tuesday afternoon, the Cook County state's attorney announced the indictment of the Chicago police officer.
It's a day Nancy Flores and her attorney say they have been waiting for ever since Flores' brother Miguel and his best friend, Eric Lagunas, were killed.
Off-duty police officer Ardelean has now been charged with reckless homicide and aggravated DUI after the Cook County State's Attorney's Office reopened the case following the public airing of a bar surveillance tape that shows Ardelean drinking at a bar.
"I think when they saw the tape on TV, they really had no choice other than to bring charges. But the odd thing is, that tape was given to me by them after they told me to my face they watched the tape and there was nothing that could be concerned about," said Dan O'Connor, Flores' attorney.
Ardelean has claimed he was not legally drunk and that most of the shots he was drinking at the bar were water.
The case against the off-duty cop was originally thrown out by a judge who ruled at a preliminary hearing there was not enough evidence to pursue felony charges. The videotape was not used as evidence.
Flores and her attorney say they are hopeful justice will finally be served.
"It's been a major battle. But again, in our hearts, we knew that something had to come out of it. I know my brother, left by them to die, something was wrong, and the battle has to come to an end," said Nancy Flores.
Lagunas' mother said in Spanish, "After 10 months, there will now be justice. This is what we were hoping for from the start, but they kept putting obstacles in our way, but we are now happy."
"We'd been assured that there's no basis for criminal charges," said Ardelean attorney Tom Needham. "So, we're puzzled and disappointed. But we're looking forward to going to court and finding out what this new evidence is and confronting it."
Ardelean will remain free for now. A bond hearing is set for Oct. 1.