Expert: ‘Messy’ DNA links alleged gunman to Tyshawn Lee killing

When police found Tyshawn Lee’s body in a South Side alley, the fourth-grader’s prized basketball was just a few feet away. Tuesday, an expert in a controversial, cutting-edge DNA test said the 9-year-old’s ball carried a link to his killer.

In the fall of 2015, a witness told police she saw Dwright Boone-Doty dribble Tyshawn’s basketball while chatting with the boy in Dawes Park shortly before Tyshawn was killed. But swabs of the ball and from a car investigators believed Boone-Doty and his co-defendant, Corey Morgan, had driven to the park didn’t turn up any DNA that was usable for technicians at the State Police lab.

So, for the first time, the Illinois State Police used “probabilistic genotyping” software to untangle the co-mingled or damaged DNA strands and hired the New Zealand-based scientist who helped create the software.

Testifying Tuesday, John Buckleton said he was reluctant to lead the testing in the Tyshawn Lee murder but did turn up “very strong support” that Boone-Doty’s DNA was on the ball and inside a black SUV found abandoned in the south suburbs that prosecutors have hinted had been wiped down with bleach.

“I was convinced by people expressing to me the importance of this case and the need for me to ‘man up,’” Buckleton said during cross-examination by Boone-Doty’s lawyer, Assistant Public Defender Michael Buresh.
“Was there a lot of pressure to solve this case?” Buresh asked.

“I believe it was considered important and they were prepared to invest resources,” Buckleton said.

Buckleton’s testimony and the STRMix findings had been the subject of hours of pre-trial hearings and multiple, lengthy filings by the defense, before Wilson earlier this year ruled the data could be used as evidence. The trial marked the first time the STRMix software had been used in an Illinois criminal court, though Buckleton testified that federal law enforcement agencies and states including Texas, California and Florida all have used the technology.

In pre-trial hearings, defense lawyers had attacked the science behind STRMix, and Boone-Doty’s lawyers are expected to put their own expert on the stand. No witness has testified to seeing Boone-Doty fire the shots that killed Tyshawn, though prosecutors have said Boone-Doty himself confessed to a fellow jail inmate about killing the 9-year-old.

Prosecutors have said that Boone-Doty and Morgan were members of a gang faction that targeted Tyshawn to avenge the murder of Morgan’s brother a few weeks earlier by a rival gang that counted Tyshawn’s father, Pierre Stokes, as a ranking member.