DALLAS (AP) _ A man who spent more than 27 years in prison has been cleared of a 1980 murder and is expected to be released as early as Tuesday, which would make him the longest-serving wrongly convicted man in the nation to be exonerated by DNA testing, his lawyers said.

James Lee Woodard, 55, of Dallas, was expected to be released on bond Tuesday, said Jeff Blackburn, chief counsel for the Innocence Project of Texas.

"After a careful review of the files in this case by our Conviction Integrity Unit, it is apparent that James Woodard did not have a fair trial back in 1981 and the results of his post-conviction DNA test exclude him as the perpetrator of any sexual assault that may have occurred, making him eligible for bond while we finalize our investigation on this case," Dallas County District Attorney Craig Watkins said in a news release.

Woodard would also become the 18th person in Dallas County to have his conviction cast aside, a figure unmatched by any county nationally, according to the Innocence Project, a New York-based legal center that specializes in overturning wrongful convictions.

Overall, 31 people have been formally exonerated through DNA testing in Texas, also a national high. That does not include Woodard and at least three others whose exonerations will not become official until Gov. Rick Perry grants pardons or the Texas Court of Criminal Appeals formally accepts the ruling of lower courts that have already recommended exoneration.

Woodard was jailed in January 1981 and sentenced to life in prison in July 1981 for the murder of a Dallas woman found sexually assaulted and strangled near the banks of the Trinity River in 1980.

The boyfriend of the dead woman, Woodard was convicted primarily on the basis of testimony from two eyewitnesses, said Natalie Roetzel, the executive director of the Innocence Project of Texas. One has since recanted in an affidavit. As for the other, "we don't believe her testimony was accurate," Roetzel said.

Woodard had previous convictions for burglary, felony larceny, marijuana possession, driving under the influence and unauthorized use of a motorized vehicle, according to Texas online criminal records.

Woodard's journey from his incarceration to expected exoneration is more complicated than most.

Like nearly all of the exonorees, he has maintained his innocence throughout his time in prison. But after filing six writs with an appeals court, plus two requests for DNA testing, his pleas of innocence became so repetitive and routine that "the courthouse doors were eventually closed to him and he was labeled a writ abuser," Roetzel said.

As recently as 2004, a court without holding a hearing denied Woodard's request for DNA testing because prosecutors said there was no evidence to test, according to court documents.

"That was a lie," Blackburn said. "We discovered there was evidence to test. This proves that the callous and cavalier attitude of the court of criminal appeals and other courts in this state toward these kind of claims should come to an end."

In letter after letter written from prison, Woodard insisted he was innocent of his girlfriend's murder. In neat cursive written on lined paper, Woodard begged officials to reopen his case.

"My Social Status in society is below you but I think everyone is entitled to justice don't you?" he wrote to one law enforcement official in 1981.

In a 1984 letter, one of several he sent to former District Attorney Henry Wade, Woodard wrote: "I have appealed to you in every way I can and now I'm tired. You seem to be adamant in your decision not to investigate my case, but I won't give up until I get this thing out into the open because it's wrong for me to be here."

Woodard finally found a sympathetic audience in 2007. Watkins, the new district attorney, had begun a program in which law students, supervised by the Innocence Project of Texas, are reviewing hundreds of requests by convicts for DNA testing.

In October, Woodard's case caught the eye of a Texas Wesleyan law student working in the program. By December, DNA testing on semen from the sexual assault excluded Woodard as the perpetrator.

But the DNA test results did not immediately free Woodard. It absolved him of the rape. But he had been convicted of murder.

"The problem is they tried it as straight murder and not rape and murder," Roetzel said. "We had to able to tie the rape to the murder to get a post-conviction release."

Prosecutors at the time believed the rapist was also the murderer, Roetzel said. This year, a forensic pathologist who studied the DNA testing results, autopsy photos, the coroner's report and other evidence concluded the two crimes "were tied together in such a way that the rape results would conclusively show who the perpetrator was," Roetzel said.

Dallas County prosecutors agree with Woodard's lawyers that he would not have been convicted had this evidence been available in 1981.

"This is happening only because the Dallas DA established this program," Blackburn said. "There is no other county in the state that this could have happened in."

Copyright 2008 The Associated Press.