DALLAS — After spending 475 days in jail, a Dallas woman has been cleared of intoxication manslaughter after her attorneys argued that prosecutors ignored exonerating evidence in her case.

On January 26, 21-year-old Saira Rascon Fierro, 21-year-old Teresa Mendoza, and 22-year-old Sam Rodriguez were involved in a car crash along the LBJ Expressway in North Dallas.

Mendoza was killed in the crash, and Fierro was charged with intoxication manslaughter and intoxication assault. Rodriguez survived.

Prosecutors alleged that Fierro was behind the wheel when the crash happened, based on the eyewitness testimony of a woman who said she helped pull Fierro from the wreck.

Yet, Fierro and her family have always maintained that the 21-year-old was never driving the car.

"It was tough for us, but we knew she wasn't guilty," sister Yamileth Rascon said. "I guess inside, she always knew she was innocent."

Fierro was put on trial for her intoxication manslaughter charge in December of last year.

However, it resulted in a mistrial with 10 jurors voting for acquittal and 2 for conviction.

This week, the Dallas County District Attorney's Office decided to try the case again.

In both trials, Fierro's attorney Ashkan Mehryari told WFAA that the only issue contested was the operator of the vehicle.

Mehryari added that all roads never pointed to his client except for what he called 'questionable' witness testimony.

"You would have thought it was an exoneration hearing, not a criminal trial," Mehryari said.

There was a blood stain left in the driver's seat of the car and per court filings, the state never had it DNA tested.

The defense argued that Fierro never received an open wound during the wreck and that a simple test of the blood would show she wasn't sitting in the driver's seat.

Mehryari also argued that Fierro had a bump on her head, indicating that she was not in the front seat where airbags deployed.

But what is possibly the most eye-opening is what Mehryari found in hundreds of pages of medical records connected to the crash.

In those records, a nurse at the hospital said she overheard Rodriguez (who owned the car) talking to his mother about the crash on the phone and how he was driving.

She even took note and put it in his file which said:

"Patient talking to mother on phone, concerned about girlfriend who was a passenger in the car. It is now learned that patient was an unrestrained driver." 

That medical note raises questions about the credibility of the eyewitness, per Mehryari.

"We knew she wasn't the driver and we knew they had the wrong person," Mehryari said.

What's even more interesting, assisting attorney Mark Lassiter said that prosecutors didn't point out this information revelation to the defense.

Rather, he and Mehryari said they had to find it themselves in those hundreds of pages of records.

Mehryari even wrote in a court filing that the DA's office, "dumped a confession in voluminous medical records, sending the Defense on a search for a needle in a haystack without knowing they were looking for a needle."

"When you have a person admitting to being the driver, that exonerates our client," Lassiter said.

Another interesting fact, a court filing said that prosecutor Katheryn Suggs tried to prevent Fierro's attorneys from, "entering the statement into evidence at the second trial, while also failing to identify the exculpatory statement as required."

However, the filing said that Suggs eventually dropped her objection and the case was dismissed mid-trial.

On Friday, Fierro's intoxication assault charge was dismissed too. Dallas District Attorney John Creuzot personally signed that document.

"I think that's a strong statement from this administration because that's not what we saw with the previous one," Mehryari said.

The Dallas District Attorney's Office sent the statement below regarding the case:

"During the retrial this week, one witness testified to additional facts that were previously unknown to the parties in the first trial. The statement cast doubt on the accuracy of her recollection of the events. Additional forensic testing had not been previously done but was done this week and the results were inconclusive, not shedding any light as to who the driver of the vehicle was.

After a thorough review of the testimony, evidence, and forensic reports, the State decided that it could not proceed in this prosecution in the interest of justice."

It's not clear if the Dallas District Attorney's Office will pursue charges against Rodriguez.

As for Fierro, her fight for freedom has only just begun. She's an immigrant, and with her charges being dismissed, she'll only be transferred to ICE custody.

Her sister is confident they can find an attorney to help her with a release, a process that will be much easier now that she's no longer facing criminal charges.

"We hope we can get her out of here," Rascon said.