On a Saturday afternoon in 1975, a 3-year-old boy wandered into the woods behind the apartment complex where he lived in Richmond, Virginia.
Four days later, the toddler's body was found floating in shallow water in the James River, fully clothed, arms folded across his chest, 9 miles from home.
From there, the horror only grew: Forensic experts told the police that the boy had a gob of semen in the back of his throat and determined that he had been strangled during a sexual assault. Alcohol and a muscle relaxant were found in his blood, according to court documents.
About a month later, in December, police arrested Marvin Leon Grimm Jr., a 20-year-old Navy veteran, picking him up after his shift at a carpeting company and questioning him for nine hours. Grimm, who had no criminal record, lived across the hall from the boy's family and had argued with them over minor issues like toys that were damaged by his lawn mower. He was married, and his first child, a son, had been born 10 days before his arrest.
After the interrogation, he confessed to abduction, the sexual assault and the murder, eventually serving 45 years in prison for the killing before being released on parole in 2020.
But as the years passed and forensic science improved, the story of the boy's death unraveled. A new analysis of the toxicology report showed that the prosecution's timeline of the crime was virtually impossible. And the only physical evidence connecting Grimm to the victim were eight strands of hair found in Grimm's car and on his coat, which a state forensic scientist said were all "consistent with" the victim, according to court documents.
Later, it turned out that none of the hairs belonged to the victim; in fact, they were from several people. More significant, Grimm's DNA was nowhere to be found in swabs from the victim's body.
And the alleged semen was not semen at all, calling into question not just the medical examiner's ruling on the manner of death but also Grimm's entire confession, since he had described a sexual assault.
"That detail had to come from the police -- it could not have originated with Marvin Grimm," said Peter Neufeld, a co-founder of the Innocence Project, which handled the case with Arnold & Porter, a private law firm. "It's a smoking gun detail which provides compelling evidence of the falsity of the confession."
On Tuesday, the Virginia Court of Appeals granted Grimm a writ of actual innocence, fully absolving him of the crime. The state attorney general, Jason Miyares, a Republican, had supported Grimm's innocence claim, writing in a court brief, "No rational trier of fact would convict him in light of all the evidence."
Grimm said that he had nearly given up in 2017, telling God that he was leaving it up to him. As he said in an interview: "If you're going to let me out, let me out. If you're going to keep me in, keep me in. I'm not going to stop worshipping you."
The appeals court noted on Tuesday that little was known about false confessions in the mid-1970s. Since then, research has shown that oppressive interrogation conditions, such as extended questioning and misrepresentation of facts or evidence by police, can induce people to say what their interrogators seem to want to hear, believing that the truth will eventually come to light.
More than 10 per cent of wrongful convictions involve false confessions, according to the National Registry of Exonerations, and the percentage is far higher in homicide cases, according to data collected by the Innocence Project.
Grimm is now among the exonerees who have served the most years in prison. The National Registry of Exonerations says that the longest time served was 48 years. All told, the registry says, the wrongfully convicted have served 25,000 years.
Much of the key evidence that linked Grimm to the killing was the work of Mary Jane Burton, a senior analyst at Virginia's crime lab who died in 1999.
Burton, who worked at the state crime lab from 1973 to 1988, was once hailed because it was discovered that she had preserved evidence that helped lead to several exonerations.
But in a recent podcast investigation of Burton's work, a whistleblower revealed that she had tried to alert officials that Burton was cutting corners and falsifying results, and an independent expert said that the serology evidence that Burton had analyzed in one of her own cases excluded the man who went on to be convicted of the crime. The podcast also noted that there were several accounts of shoddy work by Burton, and a perception that she favored the prosecution.
The podcast, Admissible: Shreds of Evidence, has triggered state reviews of close to 10,000 cases handled by Burton. But the Grimm case was still jarring, said Tessa Kramer, the journalist who produced it.
"Even after all the reporting I've done on Mary Jane Burton and the issues with her work, I was shocked to see something that egregiously bad and seemingly falsified," she said. "It makes me think about how much power these forensic results have in a case, and therefore how dangerous they can be if they're not done properly."
The Grimm case exposed other problems; the appeals court noted. Grimm pleaded guilty in exchange for an agreement that prosecutors would not seek the death penalty. But under Virginia law at the time, the crime was not eligible for capital punishment.
Grimm said his lawyers at the time had handled the negotiations and had not made it clear to him that the death penalty was not on the table.
Because of the guilty plea, it became much harder for Grimm to argue his case. The Innocence Project, a legal effort that has freed hundreds of wrongly convicted people across the country, had to lobby to change state law to allow for defendants who had pleaded guilty to test DNA evidence, Neufeld said.
Throughout it all, Grimm, now 69, said he had been denied parole "28 or 29 times." When he was finally released in 2020, he went to live with one of his two younger sisters.
Now with his parole restrictions no longer in effect, Grimm says he is looking forward to being able to travel, maybe to visit a friend in Tennessee, a niece in Kansas, or the places he lived while growing up.
He has not seen his son since the day he was arrested, and he is not sure if he will. "I don't know what he thinks," Grimm said.