The person charged with vehicular hijacking and reckless driving of a police vehicle and a postal vehicle, leading to a Bridgeview crash that left two children seriously injured March 19, died in Cook County Jail on Sunday afternoon, according to the Cook County sheriff’s office.

Miguel Alvarado, 36, was found unresponsive in the shower area of the residential treatment facility at 2700 S. California Ave. in Chicago, the sheriff’s office said in a written statement. He was brought there March 22 on charges of vehicular hijacking in Oak Lawn and aggravated possession of a stolen vehicle and aggravated reckless driving/great bodily harm to a child in Bridgeview.

Alvarado was taken to Mount Sinai Hospital, where he was pronounced dead, the sheriff’s office said. The office does not suspect foul play but is awaiting an autopsy and results of an independent investigation requested of the Illinois State Police Public Integrity Task Force.

The Cook County state’s attorney’s office said on Thursday that Alvarado failed to show up to two court hearings in the case the week before. He was detained April 1 and was due for another court hearing April 22.

Prosecutors’ petition for detainment states Bedford Park police officers were called to a Speedway on March 19, where Alvarado was allegedly “causing issues” and trying to access a locked area in the back of the gas station. The officers were reportedly familiar with Alvarado, who they released earlier that day on a misdemeanor charge.

Officers engaged Alvarado again after he walked across the street to the firehouse on Archer Avenue and caused another disturbance, prosecutors said. Alvarado accepted a ride to the train station from the officers, asking if he could first finish his cigarette.

“The defendant then ran to the Bedford Park officer’s fully marked squad vehicle and drove away,” the petition states. The officer tried to stop him but ultimately ended the pursuit due to safety risks, the petition states.

From there, Alvarado drove to Chicago Ridge and the police vehicle was disabled on train tracks, prosecutors said.

He approached a postal worker sitting in a U.S. Postal Service van in Oak Lawn and pulled her out before taking the van, prosecutors said. The two were involved in an altercation that allegedly included Alvarado punching the postal worker with a closed fist, they said.

Alvarado drove the van west on 97th Street and was traveling at about 80 mph when he collided with a black sedan driving in his path that included an adult and her two children, ages 3 and 6, the petition states.

The children remained in critical condition March 21, with injuries including multiple broken bones for one and a brain bleed for the other, the petition states.

The mother was taken to Northwestern University Medical Center, and the children to Comer Children’s Hospital in Chicago and Advocate Christ Medical Center in Oak Lawn, Bridgeview police said.

Alvarado reportedly hit two vehicles in addition to the black sedan with the three victims and unsuccessfully tried to take one person out of the car to take that car as well, the petition states.

“That victim was able to wrestle the defendant to the ground for when officers arrived on the scene,” the petition said.

ostevens@chicagotribune.com