Three people died in the Maywood crash near the intersection of Chicago and First avenues around 10:30 p.m. Thursday.
The crash knocked down trees around a home, with one car hitting the side of the home.
"I'm watching TV, then boom," said homeowner Alex E. Lathan. "It sounded like a bomb."
Police say it all started when Christopher Scotland, 18, stopped to check on Christopher McConnell, 21, in River Forest, who he said appeared to be unconscious.
Scotland said that he was driving his mother's white minivan along Chicago Avenue when he noticed the stopped car.
"Something told me, turn around and make sure the guy is okay," said Scotland. "I turned around, rolled my window down and asked him, 'Are you okay?'"
Scotland claims that McConnell, in a Honda, got annoyed when Scotland asked him if he needed help. Scotland said he called police for help and noticed that McConnell had begun chasing Scotland in his car. The cars were going 70 to 80 miles per hour.
"He comes after me - now, my first thought is not to get my mama's van hit because she would seriously hurt me," said Scotland. "I put my foot to the gas and just start driving westbound away from Harlem and he was chasing me."
Scotland ran a red light going west on Chicago Avenue to escape. Police say McConnell followed through the intersection and hit a Mercedes SUV that was traveling south on First Avenue, killing 57-year-old Nancy Tucki and her daughter's boyfriend, 36-year-old Nicholas Randazzo, both of Chicago. McConnell, of Oak Park, also died.
"I realize, oh my god, he just hit something, and I get out the car and stand next to it - I never approached his truck, I never approached the others' truck - that was an accident," said Scotland. "I stayed right next to the van throughout the whole time."
Scotland said this was the first time he has stopped to try and help someone else.
Randazzo was pronounced dead on the scene. Tucki and McConnell were pronounced dead at Loyola University Medical Center in Maywood within an hour of the accident.
Randazzo and Tucki were leaving the restaurant where Tucki's daughter worked. They were headed to the casino in Aurora.
Friends say Tucki was a stay-at-home mother who did everything for her kids, and Randazzo was a successful stockbroker downtown.
"A good kid, he did very good. He was an intelligent guy, very intelligent guy. He did nothing wrong," said Agostino Fiasche.
"She was a good mom, a great wife to her husband and she will be missed. This was a tragedy for that family's kids," said family friend and restaurant owner Anna Fiasche.
Friends remembered Randazzo Friday for his sense of humor and his faithfulness.
"He pretty much made fun of everyone; it was just for fun. He would pretty much do anything," said friend Vince Adreani. "If you needed anything, he was the first one there."
Friends say Tucki's daughter, Jenna, and Randazzo were talking about marriage, and had expected to make that announcement soon.
"There are no words to express how good these people were," said Fiasche. "Nancy wasn't just my friend, she was my sister."
Scotland was unhurt. Maywood Police Chief Tim Curry said no charges would be filed against him.
"Based on the information that we found him trying to assist calling the police department in River Forest and as well as being chased away from the area, we find no reason to file charges against this young man," said Curry.
Police said the 911 tape and witnesses' reports backed up Scotland's story.
McConnell's family said they still have questions about the circumstances surrounding the crash that their son died in, including whether Christopher McConnell really needed help.
"If that made sense to the Good Samaritan, the alleged Good Samaritan, great for him, but it doesn't make sense to us," said cousin Kurt McConnell.
Family members were stunned by the news of McConnell's death.
"He was always a caring person," said McConnell's sister. "He always wanted to put the next person before him."
Police said they are performing toxicology tests on McConnell.
"We need to find out what his condition was and what percipitated this incident," said Curry. "Once we get that back, we'll know."
The Chicago Tribune is reporting McConnell has a criminal record of drug convictions.
There were no other passengers in the vehicles, and no one else was injured in the crash, according to a spokesman for the Maywood Fire Department.
State police were called in to assist in the investigation, ISP District Chicago Master Sergeant Joe Stangl said, citing preliminary information.
The Sun-Times Media Wire contributed to this report.