EMBED >More News Videos Thursday at 10pm: One of the first modern mass school shootings happened on May 20, 1988 at Hubbard Woods School in Winnetka. Chuck Goudie investigates what changed because of this tragedy and what remains the same.

CHICAGO -- On May 20, 1988, Laurie Dann walked into a second grade classroom in north suburban Winnetka, told the students she was there to teach them about guns, and then opened fire on the classroom.The shocking school shooting, which killed one student and injured five more, was the culmination of several days of bizarre and violent behavior from a woman who was known to suffer from mental illness.According to police at the time, Dann started her day around 9 a.m. at the home of a family she previously babysat for. There she took two of the children on what she had told their parents was a previously-planned date to a carnival in Evanston. But there was no carnival; instead she took them to an elementary school in Highland Park, where she attempted to set a fire. The small blaze was quickly extinguished.Police said Dann then drove the children home at about 10:15 a.m. and, while they and their mother were in the basement, set fire to the house. The family was able to escape out a basement window and were not injured.While firefighters extinguished the house fire, Dann was already on her way to Hubbard Woods Elementary School in Winnetka.In the school, Dann encountered a boy in the hallway, pushed him into a nearby washroom and shot him, police said. She attempted to shoot two other boys, but her gun jammed. The boys ran for help.Then she walked into a second grade classroom. She was armed with two handguns. She told the teacher, a substitute, to gather her students at one end of the classroom. Their teacher did not, and tried to disarm Dann, who opened fire. Five children were struck, and 8-year-old Nicholas Corwin died of his injuries.Dann then fled the school, but found nearby roads blocked due to a funeral. She changed her route and found herself at the Andrew home. Phillip Andrew, then 20 years old and home from college, was in the kitchen with his mother when Dann burst in. She was armed, but claimed she had been raped and had shot her assailant.Andrew was able to take one gun from Dann and remove the clip, and convince her to let his parents go free. But she kept him as a hostage and, when police arrived, shot him in the chest. He managed to make it out of a back door before collapsing and being rescued by paramedics.Andrew was taken to Highland Park Hospital, and survived his injuries.Now alone in the Andrew's home, Dann maintained a standoff with police for hours. During negotiations, police brought in her parents and her ex-husband in an effort to get her to give herself up.With the home surrounded, Dann committed suicide in an upstairs bedroom.Dann had an extensive history of mental illness, had been treated for severe obsessive compulsive disorder, and had displayed odd, dangerous and violent behavior for weeks before her final rampage. The shooting at Hubbard Woods School sparked questions about the ease of which she was able to legally buy guns despite her mental state, as well as students' safety at schools. Tonight at 10 p.m. , the Chuck Goudie and the ABC7 I-Team investigate what has changed in the 30 years since this tragedy, and what remains the same.