Undercover Mom's Sting: Woman Speaks Out About Double Life

March 3, 2009— -- For more than a year, in Brooklyn, N.Y., Doreen Giuliano lived a lie.

She created a false identity, called herself Dee Quinn, changed her appearance and rented an apartment for more than $1,000 a month. The deception was designed to get close to one person: Jason Allo, whom she believed should never have been on a jury that convicted her son of murder.

"Every time I went to his neighborhood I would have to wear makeup, have my hair done, wear fake eyelashes," she told "Nightline." "So I'm trying to fix myself up for two hours and then get on the bike, or drive there and hope to have an encounter with him."

Giuliano's plan worked, and soon she was "a very nervous actor" with a fake identity and a fake relationship that lasted for months.

"It was all props," she said. "It was staged."

"I was prepared to do anything within the law," she said, to get information from Allo.

Three years ago, Giuliano's son John Giuca, 25, was convicted -- along with another man -- of murdering 19-year-old college football star Mark Fisher, who'd attended a party at the Giuliano's home two blocks from where his body was found in 2003. Fisher had been repeatedly punched in the face and then shot five times.

Giuca was condemned by the tabloids as the "Grid Kid Slayer" and sentenced to 25 years without parole. The conviction was based on testimony from three men and a prison informan, but lacked any forensic evidence.

"I'm devastated," Giuliano, 46, told "Nightline." "I'm heartbroken. This can't happen in America. We stand for fairness, for justice and it's all a joke. I'm never going to give up. I'm going to get it out there. John is innocent. John did not do this. And he's not going to go to jail for the rest of his life."

After the trial, Giuliano said there were rumors that juror Allo, 32, hadn't been honest with the judge, and that he knew of the defendants, something Allo denies.

Believing her son had not received a fair trial, Giuliano took matters into her own hands and began to follow Allo.

"I just sat in my car and watched his routine, going to work, coming back, standing on the corner with his friends," she said. "And then I wanted to try to get to know his personality without him knowing who I was. There was a time when I would wear a burka and stand 2 feet from him and listen in on his conversation with his friend. And he didn't even notice me."