Donte Johnson, 20, is accused of killing Sabina Rose O'Donnell, who was just shy of her 21st birthday when she was murdered back in June, 2010.
She had been raped, beaten and strangled with her own bra. Her nude body was found in a trash-filled vacant lot adjacent to her apartment building in Northern Liberties.
O'Donnell's mother was the first witness called on Wednesday. She told the jury she saw her daughter just weeks before the murder.
Johnson has confessed to the crime, there is DNA evidence and he was allegedly caught on surveillance camera during the hours in question. Prosecutors say Johnson was biking around the neighborhood and spotted O'Donnell as she biked home from a friend's house around 3:00 in the morning.
Assistant District Attorney Richard Sax, however, refuses to call this an open-and-shut case.
"This one is extremely painful so I can't use the word easy in any way, shape or form relative to the presentation of the overwhelming evidence in this case," said Sax.
On Wednesday afternoon, the defense team presented medical testimony claiming Johnson has an organic brain dysfunction that, they claim, throws doubt on the credibility of his confession.
The defense team will consider anything short of a first-degree murder conviction a victory.
"You take it as it comes and you try to create some reasonable doubt in the jury's mind. It's very hard to predict, sometimes, what's going to come out, especially when you're working against the mountain of evidence that we have to in this case," said defense attorney Lee Mandell.
This case is expected to go to the jury in the middle of next week.