8 things to know about our series, The Marked Man

Robert DuBoise walked out of prison in 2020 an exonerated man.

He’d been arrested at 18 for the rape and murder of 19-year-old Barbara Grams, a mall employee. After a surreal trial hinging on since-discredited bite mark evidence, DuBoise spent 37 years in prison, including a stint on death row.

In those years, he wrote and wrote, asking for someone, anyone, to take a look at his case. In 2018, the Innocence Project signed on.

The results of DNA testing in 2020 identified two men now linked to three homicides across Tampa Bay in the 1980s. They are persons of interest in other killings.

Here are some key takeaways from our series, The Marked Man.

1. Bad science sent DuBoise to prison.

The key evidence that clinched DuBoise’s murder conviction was a “bite mark” on Grams’ cheek.

Richard Souviron, a forensic dentist, testified that DuBoise’s teeth were a match. Souviron was a pioneer in the nascent field of bite mark analysis who’d testified in the case of serial killer Ted Bundy.

Since then, the National Institute of Standards and Technology and other scientific research groups have concluded that bite mark analysis has little basis in science.

A 2009 report from the National Academy of Sciences found a lack of scientific support for the notion that dentists can match a bite mark to a specific biter. Another study found that dentists struggled in determining whether a particular mark was a bite mark at all.

No studies have ever demonstrated that the makeup of people’s teeth is unique, and human skin is considered too elastic and variable to faithfully capture a bite mark. While bite mark evidence is still admissible in trials, these findings upended bite mark analysis nationwide. The American Board of Forensic Odontology no longer allows its members to testify that a mark is a “match” or give statistical likelihoods like “a million to one.” The science just isn’t there.

2. Real science got DuBoise out.

The evidence that ultimately secured DuBoise’s exoneration was stored on slides taken during a standard rape examination during Grams’ autopsy in 1983.

The slides sat in the local medical examiner’s office for decades. Their existence was unknown to investigators until the Hillsborough state attorney’s office conviction review unit in 2020 examined DuBoise’s case and a detective suggested checking the morgue for evidence.

When tested, DNA on the slides did not match Robert DuBoise.

Further testing, unavailable at the time of DuBoise’s conviction, linked the results to two men — Amos Robinson and Abron Scott. They had no connection to DuBoise and were in prison for a different murder.

3. One of the men suspected of being Grams’ real killers pleaded guilty. The other awaits trial.

Scott and Robinson were charged in 2022 with Grams’ murder.

In 2023, Scott described to investigators his memory of the night Grams died 40 years earlier. He said he and Robinson crossed paths with her as they walked North Boulevard. Scott described watching, smoking a joint, as Robinson raped Grams and beat her with a wood board.

This spring, Scott pleaded guilty and got an additional life sentence. He has agreed to testify against Robinson, who faces a possible death sentence. Robinson has denied involvement.

Scott said he didn’t know the young woman was dead until months later, when Robinson told him someone else — Robert DuBoise — had been arrested.

4. Robinson and Scott have surfaced in other murder investigations. Some remain unsolved.

The same day Scott and Robinson were indicted for the Grams murder, a grand jury charged them with another killing.

Linda Lansen, a 41-year-old mother, was found shot to death on July 11, 1983 in Town N’ Country. Her unsolved case was among several that received renewed attention after DuBoise’s exoneration helped point investigators toward Scott and Robinson.

Investigators in 2007 identified a fingerprint lifted from Lansen’s car window as belonging to Scott. But DNA testing at the time was unable to make a link, investigators said.

In 2021, testing identified DNA from Scott on a bloody towel at the murder scene and DNA from both men on Lansen’s body. Lansen’s daughter, Dessa Willson, who was 7 when her mother was killed, confronted Scott in court, saying she never believed this day would come.

“You ruined my life,” she told him. “You basically took away my entire childhood.”

Scott wept, asking for forgiveness.

5. The state and the city of Tampa both gave DuBoise compensation, but it wasn’t easy.

Florida law provides compensation for people who have been exonerated — unless they have prior felony convictions.

DuBoise had a handful of teenage convictions for burglary and theft. To get the money, the Florida Legislature had to pass a bill to grant an exception. At stake was $1.85 million — $50,000 for each year he was wrongfully incarcerated. A legislative official examined the case, concluding that he was indeed innocent. He received his compensation in 2023.

Sponsor Sen. Erin Grall (R-Vero Beach) called the bill “an act of legislative grace.” She went on: “I actually believe that we should be asking him for his grace, rather than him asking us for ours.”

DuBoise sued the city of Tampa, the retired Tampa police detectives who arrested him, and the forensic dentist who matched his teeth to the victim’s wound.

The complaint accused the investigators of violating DuBoise’s rights to due process and the city of failing to properly train their officers. It claimed that detectives conspired with a dentist they could “count on” to make a match. The suit accused detectives of excluding evidence that could have helped DuBoise — chiefly that they’d pressured their jailhouse witness to deliver a confession tale they knew to be false.

DuBoise’s lawyers hired a policing expert who said the detectives overly relied on bite mark evidence and had “tunnel vision” after DuBoise became a suspect.

The retired detectives and the dentist all disputed in court that there was any evidence to support the claims.

The case reached a settlement in February, wherein the city agreed to pay DuBoise $14 million. The defendants admitted no wrongdoing.

6. A conviction review unit in Hillsborough County helped identify other wrongful convictions.

In 2018, the state attorney’s office introduced a unit to re-investigate cases in which they’d secured a conviction against someone with a plausible claim of innocence.

The idea was that prosecutors, with easier access to evidence and witnesses, could quickly help right wrongs in the event a prisoner proved to truly not have committed the crime. Similar entities have been established in prosecutors’ offices nationwide.

The conviction review unit was instrumental in proving DuBoise’s innocence and within a year helped another wrongfully convicted man walk free. Tony Hopps spent 31 years incarcerated for a Tampa armed robbery before a review led to his conviction being overturned.

Hopps’ conviction rested on the recollection of the victims, who’d been accosted by a gunman at their motel room on S Dale Mabry Highway. They selected Hopps’ image from a photo array. But the review found problems with the way the photos were assembled and shown. The gunman they recalled was muscular, with a mustache and no beard, but Hopps was described as skinny and bearded.

New witnesses corroborated Hopps’ alibi. The review concluded there was no valid evidence that Hopps committed the crime. He went free.

His case was similar to that of Cornelius Marion.

Marion also spent three decades in prison for a Tampa robbery that largely hinged on the victim’s selection of his image in a photo array. The Innocence Project of Florida hired an expert in eyewitness identification research who identified more than a dozen problems with the procedures used in Marion’s case.

Marion went free in February 2023.

7. Police investigations have advanced since Robert DuBoise was arrested.

In 1983, police investigations relied greatly on what detectives gathered by talking to people.

“We were gumshoe guys,” former Tampa police Detective K.E. Burke said in testimony during DuBoise’s federal lawsuit. “We trod on the streets and we trod in the alleys and we trod places we could find information.”

Investigative technology, like fingerprints, was not nearly as advanced as it is today. DNA testing did not exist. Today, cell phone signal analysis and ubiquitous surveillance videos frequently play a role in investigations.

“The credibility of our criminal justice system requires scrupulous accuracy and adherence to the highest investigation standards,” Tampa Mayor Jane Castor said in a statement after the City Council approved the settlement in DuBoise’s lawsuit. She said the department had advanced “light years.”

DuBoise believes today’s technology would have prevented him from being falsely accused.

“All they’d have to do is ping my phone and they’d see I wasn’t there,” he said.

8. The Conviction Review Unit in Hillsborough looks different today.

The conviction review unit that discovered the evidence that helped exonerate DuBoise is in flux.

The attorney who most recently led the unit left the Hillsborough State Attorney’s Office early this year. While interviewing new candidates, a senior attorney reviews petitions from people who claim to have been wrongfully convicted, a spokesperson said.

A creation of former State Attorney Andrew Warren, the unit’s work has become less publicized since Warren was removed from office in 2022 by Gov. Ron DeSantis.

A state attorney’s spokesperson said the department’s procedures have not changed under Suzy Lopez, the longtime prosecutor appointed to replace Warren, citing the release of three prisoners under Lopez.

In 2023, for instance, the unit helped facilitate the release of Cornelius Marion, though only through a reduced sentence. Marion’s conviction remains on the books, as do the convictions of the two others who were freed.