Felony Murder Charge Dropped in Killing of David Dorn

Mark Jackson, an unwitting accomplice to murder, pleaded guilty to robbery and burglary

Mark Jackson, 24, saw his charges greatly reduced in connection to the death of retired police officer David Dorn after he testified for the prosecution. - COURTESY ST. LOUIS POLICE
COURTESY ST. LOUIS POLICE
Mark Jackson, 24, saw his charges greatly reduced in connection to the death of retired police officer David Dorn after he testified for the prosecution.

The second individual charged in connection to the June 2020 murder of retired police officer David Dorn pleaded guilty today to significantly reduced charges.

Mark Jackson, 24, appeared in court today, wearing an orange jumpsuit with City of St. Louis Corrections emblazoned down the back. With his attorney Terence Niehoff, the cuffed Jackson accepted a plea agreement with the circuit attorney's office in which Jackson pleaded guilty to charges of robbery and burglary, both felonies.

Jackson was initially charged with felony murder, robbery, burglary, stealing and three counts of armed criminal action.

Under the plea agreement, Jackson's 15-year prison sentence is suspended, and he will serve probation. He has been detained in the City Justice Center since his arrest in June 2020.

The charges stemmed from June 2, 2020, when, around 2:30 a.m., amid widespread chaos in the wake of the murder of George Floyd, Dorn was killed while attempting to stop looters at Lee's Pawn & Jewelry on Dr. Martin Luther King Drive. When Dorn arrived at the scene, he fired several shots in the air, hoping to disperse the crowd. A few moments later, 26-year-old Stephan Cannon shot Dorn four times.

Earlier this week, Jackson testified against Cannon, saying that he drove Cannon to Lee's that night and also drove him home. Jackson said that he only intended to join in the looting of Lee's and didn't know that Cannon was armed. Jackson testified that the following day, Cannon admitted to him he killed Dorn.

With Jackson's testimony, the jury found Cannon guilty of first-degree murder. Unless the verdict is overturned, Cannon will spend the rest of his life in prison.


Because Jackson drove Cannon to and from the scene and also participated in the looting, he was charged with felony murder — a charge used by prosecutors against individuals whose participation in lesser criminal acts, in this case looting, inadvertently lead to someone's death. That charge, along with charges of armed criminal action and stealing, were dropped as part of the plea agreement.

At the hearing today, both Niehoff and prosecutor Marvin Teer spoke positively of Jackson for the testimony he gave leading to Cannon's conviction.

Jackson's coming froward "nailed the coffin shut on Mr. Cannon," Niehoff stated.

Niehoff added there likely had already been repercussions resulting from Jackson's cooperating with law enforcement. Jackson's mother's home had been burned down, Niehoff stated.

Niehoff added that Jackson now faced risks as someone who others might think of as a "snitch" because of his involvement in a high-profile trial.


Prosecutor Teer also stated that he had a message from Ann Dorn, David Dorn's widow and herself a longtime police officer. Since her husband's death, Ann has become active in philanthropic work, and she hoped that she could work with Jackson and help him get his life back on track.

click to enlarge Ann Dorn speaking to media after a jury declared Stephan Cannon guilty of murdering her husband, David Dorn. - Ryan Krull
Ann Dorn speaking to media after a jury declared Stephan Cannon guilty of murdering her husband, David Dorn.

"She wants to reach out to him, and wherever he goes next," Teer said afterward to reporters. "She's all in."

Teer also stated that Jackson had never before been charged with a violent crime.

Prior to the sentencing, Teer spoke to Jackson directly as he sat at the defendant’s table. Teer said he thought Jackson was a good young man who got caught up in trouble and had to face the consequences.