Police searched Tuesday for three missing Chicago children whose mother was found dead with a plastic bag over her head, as officials learned she had an existing order of protection against her husband.

Sophia Garcia, 30, was found dead in her home around noon Monday, according to the Cook County medical examiner's office. Authorities said they were looking for 32-year-old Benito Casanova, whom they described as Garcia's husband.

Garcia was given an order of protection against Casanova in July 2006 because she claimed he threatened to kill her and commit suicide, the Chicago Sun-Times reported. But, because Garcia failed to appear for a court date a month later, that order was lifted, the Sun-Times reported.

In February of 2007, she was again granted an order of protection that was in effect until March 2009, according to the report.

The new protection order stemmed from a Valentine's Day visit in 2007, when Casanova took Garcia's keys. He denied taking them and they were returned a day later, left near a window with a note reading, 'Here are your keys. Goodbye,' the newspaper said.

Garcia later found Casanova in her home, according to court documents.

"I went into the bedroom and pulled the blanket on the bed. And he came at me. He had entered my home and hid until I returned. He chocked [sic] me telling me that he was going to KILL me because I did not want to be with him," Garcia said in court documents cited by the Sun-Times.

"He ALWAYS tells me that he IS going to KILL me if I don’t take him back, then kill himself. He said that if I go to the police, he will ‘take it out on my sisters,’" she continued. "He says he will kill me and then himself so he doesn’t go to jail. I am very, very scared.’”

The current protection order barred Casanova from having any contact with Garcia, her sisters and his three children. It also prohibited him from going near Garcia's 1997 Oldsmobile Cutlass, to the children's school or to a Target store in Evanston, Ill., where Garcia worked, the Sun-Times reported.

Illinois State Police issued an Amber Alert Monday evening for Garcia's children, who range in age from 6- to 11-years old. The two boys and a girl have not been seen since last seen Friday, police said.

Casanova has not been charged in connection with the case. There was no telephone listing for a Benito Casanova in Illinois.

Casanova drives a 2002 silver or gray Dodge Dakota, with one Illinois license plate, police said. He is 6-foot-1 and 230 pounds, with brown hair and brown eyes.

Oscar Casanova, 6, is 4 feet tall and weighs 60 pounds. Karla Casanova, 7, is 4-foot-1 and weighs 75 pounds. Fernando Casanova, 11, is 5-feet and weights 130 pounds. All the children have brown hair and brown eyes.

Anyone with information should call 911, officials said.

Click here to read more on this story from the Chicago Sun-Times.

The Associated Press contributed to this report.

A photo originally accompanying this story was incorrectly identified by the source of the photo as Benito Casanova. Once FOXNews.com was informed of the source’s error, the photo was replaced. FOXNews.com regrets the error.