Click in the Eyewitness News Story Window above to watch Leanne Suter's report from the scene.
"Just scared to think of that. It is not suppose to happen that way. It just seems to young," said Brent Hellesen, a neighbor of one of the victim's.
The CHP says that 27-year-old Steven Quintero was driving northbound in the southbound I-5 lanes. He slammed head-on into a silver Nissan Sentra carrying four people and died at the scene.
The impact of the collision was so powerful that 20-year-old Arielle Estremo, driver of the Sentra, was crushed to death, and passenger 20-year-old Chauncy Reid was also killed instantly.
Two male passengers, ages 18 and 19, in the Sentra were seriously injured and were rushed to Los Angeles County-USC Medical Center.
Investigators say several friends of the victims witnessed the crash as they were following behind the vehicle. The whole group had just left a club in Hollywood and was apparently returning home to Orange County when the Sentra slammed head-on into the wrong-way driver.
"They saw the headlights and the Nissan Sentra applied their brakes. They saw them veer over to the right and both cars went up in the air. That is what she said as she went past," said CHP Sgt. Brian Gonsalves.
Investigators do not know where Quintero entered the freeway going the wrong way or why. Officials are waiting on toxicology tests to determine if drugs or alcohol may have been a factor.
Friends say that the four in the Sentra were all part of a close group that worked together at Knott's Berry Farm's Halloween Haunt.
"I never thought that would happen to any of my friends. I feel bad for saying this, but I feel lucky that I wasn't in the car. And our friend Jackie could of gone last night to, but she said no," said Chelsa Mullins, one of the victim's friends.
The witnesses rushed to help their friends. CHP officers, who were close by at the time, heard the crash and also rushed up onto the freeway to help the victims.
The southbound 5 Freeway through Commerce was closed for more than three hours as morning traffic continued to pile on to the freeway. The scene was cleared and all lanes re-opened at about 6:40 a.m. on Friday.