Mugshot of Eduardo Lerma. (Illinois Dept. of Corrections)A Chicago man convicted of gunning down his neighbor will get a new trial, because he was not allowed to bring an expert on eyewitness testimony to testify during his trial.

Eduardo Lerma, now 36, was convicted in 2012 of the 2008 murder of Jason Gill, his across-the-street neighbor. But now Lerma will get a whole new trial, the Illinois Supreme Court ruled unanimously on Friday.

“We not only have seen that eyewitness identifications are not always as reliable as they appear, but we also have learned, from a scientific standpoint, why this is often the case,” wrote the Supreme Court judges.

Lerma and Gill had been friends for years. One night in May 2008, Gill was sitting on his porch steps with his friend Lydia Clark when a person with a gun and a hooded sweatshirt over their head came up and fired multiple shots, according to court documents.

Gill had shielded the body of Clark, who then dragged both herself and her friend inside. Gill’s father asked who had shot them, and both the dying Gill and Clark said it had been “Lucky” – the known nickname for Lerma.

No physical evidence tied Lerma to the crime.

Clark selected Lerma out of a lineup the next morning, and told detectives she had seen “Lucky” from across the street many times over the previous year, and that she “knew” him.

READ MORE: Initial Eyewitness Confidence in IDs Could Be Crucial in Determining Accuracy

But there were confounding factors, according to the court. The outside of the house was dark, since it was nearly midnight at the time of the attack, the killer’s face was obscured by the hood, there was the suddenness of the attack and the panic of seeing the weapon – and Clark even later admitted she did not “know” the suspect beyond seeing him on the street once or twice before.

His defense attorney attempted to bring an expert to tell the jury in his 2012 trial about these complicating factors, but was rebuffed three times during the trial.

“The only evidence of defendant’s guilt in this case is the eyewitness identifications made by Clark and Gill,” the Supreme Court judges wrote. “There is no physical evidence tying defendant to the crime, and defendant neither confessed nor made any other type of incriminating statement.

“In other words, the State’s case against defendant hangs 100 percent on the reliability of its eyewitness identifications,” the judges added.

Lerma was subsequently convicted of first-degree murder and other counts, and sentenced to 45 years in state prison.

But now both the appeals court and the state Supreme Court have found the trial court’s refusal of two eyewitness experts in Lerma’s defense was an “abuse of discretion.”

The case is now being sent back to the lower court for a whole new trial.

“The trial court’s initial ruling denying the admission of (the) testimony was itself an abuse of discretion because the reasons the trial court gave for that ruling amounted to ‘little more than a series of conclusions based on its personal belief’ that acquaintance identifications are accurate and therefore not a proper subject for expert testimony,” the judges wrote in their latest decision, decided 7-0, and published on Friday.

The Innocence Network filed an amicus brief, in which they urged the court to set precedent in allowing juries to hear the complicating factors of eyewitness identification.

"Courts across the country in almost every jurisdiction have abandoned earlier skepticism of eyewitness experts and have either favored such testimony or treated it the same as other expert testimony," wrote the Network attorneys.

Karen Daniel, director of the Center on Wrongful Convictions at the Northwestern University School of Law, said the decision certainly sets precedent in Illinois, and ensure experts can come in and establish a "more realistic" set of criteria for juries to follow while considering eyewitness accounts.

"It's a big deal," Daniel said.

Eyewitness accuracy has been the focus of intense scrutiny and scientific research since the 1990s. The recent spate of exonerations by DNA evidence most frequently overturned convictions that had been obtained by false eyewitness accounts, according to several pieces of research. The Innocence Project has stated that eyewitness misidentification is the single most prevalent cause of the wrong convictions in the U.S. – and they have estimated it played a role in 70 percent or more of the 330 wrongful convictions overturned by DNA since 1989.

A study last month in the Proceedings of the National Academy of Sciences found that shoddy eyewitness testimony is often reinforced during interview with investigators, and during the legal process. The researchers from the University of California San Diego instead recommended that investigators take into account the confidence level of the initial identification, which is a better marker for accuracy – and can help pointed detectives the right direction.

Lerma remains locked up at Stateville Correctional Center. His projected parole date is in 2053.