HOUSTON,Texas (KTRK) -- A woman was killed after getting out of her vehicle to check on a passenger early Sunday morning on the Katy Freeway, police said.

Houston police were called to the inbound lanes of the Katy Freeway between Kirkwood and Dairy Ashford at about 3 a.m.

Police said a white Toyota Sedan pulled over and parked on the shoulder after a passenger in the back seat of the car started feeling sick. That's when the woman who was driving got out to check on the passenger.

A white Hyundai Sedan going eastbound exited the mainlanes and struck the rear of the woman's vehicle, according to police. The woman was thrown and died at the scene.

"The lady there was already passed away," said a security officer at the scene. "Like another lady was pushing on her lungs in order for her to survive, but she didn't survive."

Police said they have reason to believe the driver of the Hyundai Sedan was intoxicated. He has been charged with intoxication manslaughter.

"The other driver was crying and screaming," said the security officer. "He said 'I didn't do anything.' He thought I was a police officer, but I told him I was security. I told him I didn't see it happen and that he should calm down."

The sick passenger is expected to be OK after suffering minor injuries, police said.