(CNN) -- Houston prosecutors will ask a court Thursday to formally exonerate a Texas man after DNA tests ruled out his guilt in a rape for which he served 17 years in prison.

George Rodriguez was freed in 2004 after an appeals court found that faulty scientific evidence had been used against him in his 1987 trial. Prosecutors didn't retry him, citing concerns about having the victim -- who had identified Rodriguez as one of her two attackers in a police lineup -- testify again.

State officials had denied his request for a pardon, but Harris County District Attorney Patricia Lykos agreed to review his case after she took office in 2009.

New DNA tests on the forensic evidence in the case came back February 22 and conclusively ruled out Rodriguez, now 50, Lykos said in a statement Wednesday afternoon.

"When this scientific inquiry began, there was no legal requirement or mandate for any further work to be done by our office, because the case had been dismissed," Lykos said. "Instead, we acted on the most important obligation of all -- to see that the truth emerges, and that justice is done. Today, we can state that an innocent man has been vindicated."

The Harris County District Attorney's office will ask a judge to formally declare Rodriguez innocent at a Thursday hearing, she said.

Lykos, a Republican, campaigned on promises to reform the prosecutor's office in Texas' largest city, and she has drawn praise from defense lawyers for creating a post-conviction review process to examine new evidence. The Innocence Project, which won Rodriguez's release in 2004, gave her an award in 2010 for that program.

Another man, Manuel Beltran, is now serving a 60-year prison term in connection for rape. The DNA testing also confirmed that another man, now dead but long considered an alternative suspect, also assaulted the victim, who was 14 at the time.