Updated 10/06/14 – 3:46 p.m.

OAK LAWN, Ill. (CBS) — Two nuns and an elderly man were killed Sunday, when the man ran a red light, and plowed into cars stopped in the oncoming lanes in Oak Lawn. Eleven other people were injured in the wreck, two of them critically.

CBS 2’s Susanna Song reports the pickup truck driver was speeding before he smashed into ten vehicles stopped at a red light at 95th Street and Cicero Avenue in Oak Lawn around 4:30 p.m. Sunday.

Oak Lawn police Division Chief Randy Palmer said the man “was driving at a high rate of speed, traveling westbound on 95th street. As the vehicle approached the traffic light at 95th Street and Cicero Avenue, the light was red for westbound traffic. The speeding vehicle then crossed over into the eastbound lanes, went through the intersection, striking several cars.”

Two nuns from Little Company of Mary Hospital were in the first car struck in the crash. Sister Jean Stickney, 86, and Sister Kab Kyoung Kim, 48, were killed on impact. Little Company confirms a third nun in the car was injured in the crash and is hospitalized in stable condition.

The driver has been identified as 81-year-old Edward Carthans. He also died at the scene.

Paramedics treated 23 people at the scene. Eleven were sent to the hospital, including two who were listed in critical condition at Advocate Christ Medical Center in Oak Lawn. Most of the other injuries were minor.

Oak Lawn Fire Chief George Sheets called the crash “the most violent and most bizarre” he’s ever seen.

“To put this into perspective, as Chief Palmer said, that he thought it looked like tornado came through. In speaking with some of my firefighters, it was more … like a staged movie set; in that it was such a violent crash, and it was just unbelievable to see so many cars, so many people that were needing aid,” Sheets said.

Witnesses said the truck went airborne, spun around, and ended up facing east.

At least one person posted video of the aftermath of the crash on YouTube, as stunned drivers and passengers were getting out of their cars to wait for police and paramedics.

“I saw it flip, and the smoke went everywhere. He took out all these cars,” one person could be heard saying on the YouTube video.

Police said they were working on a timeline, tracking Carthans’ actions before the crash, to find out why he was speeding.

The incident started three miles away, at 95th and Western Avenue. A witness told police, while stopped at the light at 95th and Western, he saw Carthans slumped over, approached him, and offered to help, but Carthans sped away.

“He was stopped at the light, and this person saw him slumped at wheel. They didn’t know if he was having a medical emergency, or if he had fell asleep,” Palmer said. “This individual approaches, and has a conversation with him, I believe. We don’t know how long that conversation was, but he states at that point that he’s okay, because that person did volunteer to park the vehicle for him if was in distress.”

A short time later, Carthans apparently struck three cars at 95th and Keeler Avenue. No one was hurt in that crash.

Police said it’s too early to know if alcohol was a factor in the crash. Investigators were interviewing Carthans’ family to find out his medical history.

It also will take time to determine his truck’s speed at the time of the crash.

Dennis Reilly, President and C.E.O. for Little Company of Mary Hospital, said in a statement, ““On behalf of the Board of Directors, Physicians, Administration and employees, we send our deepest sympathies and condolences to Sr. Jean and Sr. Anna’s families. They were compassionate women who devoted their lives to caring for others. We continue to pray for all who were involved in yesterday’s accident.”