He's 25-year-old Ernesto Lucero. He's believed to be a transient from out of state.
Earlier in the day, police documented the scene and took swabs of dried blood where the suspect attacked the female shopper as she was about to get in her car.
"Some sort of conversation occurs, she ends up handing her keys to this person, at which time he punches her in the chest," said Orange Police Sgt. Dan Adams. "He must have had something in his hand or between his fingers because she does have a puncture wound."
It happened in broad daylight in the parking lot of a shopping mall.
"It was around 9:30 when we hear some screams or somebody yelling," said local employee Juan Ramirez.
Ramirez said he could see the woman was injured. Two witnesses were already helping her.
"The lady went to the floor and then we saw the blood," said Ramirez. "The car had already left."
Police say the suspect took off in the woman's car. The victim was left critically injured.
Adams said one witness tried to help the injured woman, while another witness tried to stop the suspect.
"(He) actually was banging on the window, trying to get him to stop the vehicle," Adams said.
One witness believes the suspect approached her less than 10 minutes before he attacked the victim.
"He asked me, he says, 'Do you have a dollar?' and I said 'No I do not,' and he just slowly backed away from me, and I went ahead and got in my car," said Orange resident Anne Spangenberg. "It could have happened to me. I hope and pray that she's OK and she'll get through."
Police apprehended the suspect as well as the stolen vehicle around 2:30 p.m.
Nearly four hours after the attack, authorities made an arrest after someone saw the suspect in Villa Park and called police.
"He was found to be in possession of a knife," said Adams. "We do believe that we have the right suspect. We've obviously got the car and we're very happy that this has come to this conclusion."
Police did not release the suspect's name or photo Monday afternoon because a number of witnesses still have to positively identify him. He is in his mid-20s, according to police. They believe he may be a transient. His address is out of state.
The victim is in her late 40s. She went into surgery after the incident and was in critical condition Monday afternoon.