When Sherman Brown was convicted and imprisoned in the brutal killing of a 4-year-old Virginia boy, the Vietnam War was still raging and the Watergate was just a hotel, not a scandal.

Then 22 years old, he maintained his innocence at the time and as each decade faded into the next. Now, after nearly a half-
century behind bars, Brown is petitioning Virginia’s Supreme Court, saying DNA collected from newly recovered evidence indicates that he could not have committed the murder.

Justices now will have to weigh whether that genetic evidence is strong enough to warrant overturning his 1970 conviction in Albemarle County.

If Brown, 69, is exonerated, he would be among the ­longest-serving prisoners to be cleared of a crime in the history of Virginia and the nation. It would be an extraordinary turnabout for a man who was initially sentenced to death before the sentence was reduced to life.

“Recent DNA testing demonstrates by clear and convincing evidence what I have maintained for over 45 years: that I am innocent of this crime,” Brown wrote in his writ of actual innocence filed in early October and first reported by the Richmond Times-Dispatch. “The evidence against me at trial was deeply flawed.”

Sherman Brown, seen in 2010, was convicted in 1970 of murdering a 4 year-old boy. (Department of Corrections)

Brown was convicted of first-degree murder after a vicious 1969 attack near Charlottesville, Va., during which a woman was beaten, stabbed and possibly raped in her home. The same man also fatally stabbed the woman’s 4-year-old son, leaving him face down on his bed.

The mother survived and identified Brown as her attacker. He was also linked to the crime via a type of fiber and hair analysis that the FBI in recent years has acknowledged is flawed, in part after reporting by The Washington Post.

Brown writes in court filings that new tests ruled him out as the source of a partial male DNA profile found in a recently recovered slide containing a vaginal swab taken from the woman after the attack. Neither the woman nor her son are identified in recent court records.

The tests also showed a greater than 98 percent chance that the material did not come from the woman’s husband, according to the filing. The woman recently told prosecutors she had a monogamous relationship with her husband, Brown’s attorneys said in the court papers, arguing that the DNA must have come from an unidentified third man who was the actual attacker.

Brown’s attorneys, who include lawyers from the ­Mid-Atlantic Innocence Project and New York’s Innocence Project, said that the type of Y-chromosome DNA recovered from the swab cannot be matched against DNA samples of known perpetrators contained in state or federal databases.

Virginia Attorney General Mark R. Herring’s office has not filed a response to Brown’s writ of actual innocence and another writ of habeas corpus claiming that prosecutors relied on the discredited hair and fiber analysis. Albemarle County prosecutors did not respond to a request for comment.

“As with all such petitions, we will closely examine and consider the claims and evidence as we prepare a response for the Supreme Court,” Michael Kelly, a spokesman for the attorney general’s office, wrote in an email.

Brown had recently returned from serving in the Vietnam War when the horrific events of Oct. 1, 1969, unfolded. Prosecutors said at trial that a man knocked on the door of the woman’s home that afternoon.

The woman went to the door with her 4-year-old son and opened it. The man asked for a drink of water. After a brief conversation, prosecutors said, the man propositioned the woman for sex and the woman repeatedly refused. Prosecutors said the man told her, “I’m so sexed up, I don’t know what to do.”

Soon after, the woman vaguely remembered receiving painful blows to her side and was knocked unconscious, prosecutors said.

Later that afternoon, the woman’s sister-in-law came to the house and found the woman beaten and stabbed. Her underwear had also been removed. The 4-year-old boy was found covered in blood on his bed, prosecutors said. He had been beaten and stabbed several times.

Prosecutors argued at trial that the suspect raped or tried to rape the woman and attacked her and killed her son to try to get rid of any witnesses. An analysis of the woman’s vaginal swab performed after the attack indicated the presence of sperm, according to Brown’s filing.

At trial, the woman was the sole eyewitness who identified Brown as her attacker. The woman testified that she had smoked a cigarette with him during a previous 15-minute encounter.

In his filings, Brown denies ever meeting the woman and said she might have misidentified him because they were of different races, among other factors. Brown is African American; the woman is white.

At trial, an FBI agent testified that Brown’s hair was found on a sweatshirt that also contained fibers that matched a robe the woman was wearing during the attack, tying Brown to the crime.

The woman’s testimony and forensic evidence was enough for an all-white jury to convict Brown after a brief deliberation. He was sentenced to death.

Brown was on Virginia’s death row when the Supreme Court struck down the state’s death penalty in 1972. Brown was resentenced to life, before the death penalty was reinstated.

In 2008, the Innocence Project reached an agreement with the Albemarle County prosecutor’s office to begin DNA testing in the case. After an audit, the Justice Department also recently told Brown’s attorneys that the FBI agent erred in his analysis of the hairs found on the sweatshirt.

But the true break came last year, when members of the University of Virginia’s Innocence Project discovered the slide containing the vaginal swab at the school’s Department of Pathology.

More than 40 people have been exonerated of crimes in Virginia, according to the National Registry of Exonerations. If exonerated, Brown would join Earl Washington Jr. as the only other person to have sat on death row in the state before being cleared of a crime, if the Supreme Court rules in his favor.

There are a number of steps before that could happen. The Virginia Supreme Court stayed the writ of actual innocence for 90 days so that additional testing can be done to try to conclusively exclude the woman’s husband as the contributor of the male DNA found in the vaginal swab.

The state must respond to Brown’s filing. Then, the Supreme Court will decide whether to hold oral arguments before rendering a decision. After 46 years, Brown will have to wait a bit longer for his claim of innocence to be decided once again.

“It’s very tragic to think someone has been in prison for four decades and he may actually be innocent of the crime,” said Susan Friedman, an attorney with the Innocence Project.

Jennifer Jenkins contributed to this report.