CHICAGO --The trial began Wednesday for a homeless woman accused of starting a fire that killed four people in Chicago's Wrigleyville neighborhood last year. Mary Smith is charged with arson and first-degree murder. Prosecutors say Smith set fire to a three-story building as the victims were sleeping. The fire broke out in March of last year. Investigators say Smith lit a dollar bill on fire inside the door of the building in what she said was an effort to stay warm. Smith waived her right to a trial by jury, which means that it will be up to a judge to determine her guilt or innocence. And while no one, not even her defense attorney, disputes that Smith was in some way responsible for setting the fire, the big question is whether Smith, who is a diagnosed schizophrenic, knew what she was doing. The defense says that she had a long history of mental illness and was not aware of her actions. Prosecutors say she not only knew what she was doing but also walked away from the fire without alerting anyone. The trial had been delayed for many months because of questions of whether she was or wax not fit to stand trial. But 14 months after the fire it has begun. Among those testifying were the parents of the fire's four victims. "It isn't going to change anything. Those four young people are gone forever, from our lives," said Sue Pilgreen, victim's mother. Originally from Belvidere, roommates Jennifer Carlson, 24, and Jason Bowers, 23, were hosting childhood friends Jerod Pilgreen, 21, and Joseph Schultz, 23, at their apartment at 3553 North Fremont the evening of March 10, 2007. They were asleep when prosecutors say Smith, who had broken into the building, took a dollar bill and lit it to stay warm. It was another friend, Donald Black, who, on his way out of the building before the fire, gave Smith the bill. He identified her in court Wednesday. Prosecutors played a two-hour tape of what they call Smith's confession. The tape shows Smith incoherent and rambling, something which defense attorney Jacqueline Ross said she will use to show that her client was legally insane at the time. On Wednesday, even the victims' loved ones say they understand the circumstances and simply want Smith off the street. "We just want her to be helped and not to be free to walk around. Just give her the help she needs and let it be. We can't change anything else," said Brandy Pauley, victim's friend. And while the trial does not bring Jennifer, Jason, Joe or Jerod back, what it does accomplish, say the families, is to bring them a sense of closure. "A day doesn't go by that I don't think of him at least once an hour. And it's been a year," said Sue Pilgreen. "Last year we mourned and mourned, and this year we decided we would celebrate everything she liked, everything that she loved doing," said Barb Carlson, victim's mother. On Thursday, it is the defense's turn to present their case and they are reportedly going to bring to the stand two psychiatrists that will testify that Smith was insane at the time of the fire. And that what is more, it is only a very heavy dosage of psychiatric drugs that have rendered her temporarily fit for trial.