The looter convicted of murdering a retired St. Louis police captain during riots that unfolded after George Floyd's killing is expected to be sentenced on Tuesday. 

Stephan Cannon, 26, was found guilty in July of first-degree murder in the death of 77-year-old retired St. Louis police Capt. David Dorn. 

Dorn was fatally shot while investigating alarms at a friend’s pawn shop on June 2, 2020. The retired captain fired warning shots into the air to disperse looters who were ransacking the business as he approached the building. Prosecutors argued that Cannon deliberated his actions when he walked to a corner near the pawn shop and fired 10 shots at Dorn.

Cannon’s attorneys argued the state had not provided any physical evidence linking him to the shooting and based their case largely on testimony from an unreliable witness, the St. Louis Post-Dispatch reported. However, prosecutors said Cannon was the only person standing on a nearby corner from where the shots originated.

DAVID DORN MURDER: ST. LOUIS MAN FOUND GUILTY IN DEATH OF RETIRED POLICE CAPTAIN DURING NIGHT OF LOOTING

David Dorn in uniform

David Dorn, a retired police captain, was protecting a friend's pawn shop on June 2, 2020, when he was killed. (Missouri Department of Public Safety)

St. Louis looter Stephan Cannon's mugshot

Stephan Cannon mugshot. (St. Louis Metro Police Department)

After the slaying, investigators reportedly recovered a pistol, televisions and pieces of Cannon’s dreadlocks from an apartment where he was staying, but law enforcement did not locate the handgun that Cannon is believed to have used in the shooting.

Lead prosecutor, Marvin Teer, told jurors in July that Cannon deliberated before he shot "a good man who dedicated his entire life to doing nothing but helping others."

Cannon’s lawyer, Brian Horneyer, said in his closing argument that police had "tunnel vision" when they charged Cannon without any physical evidence. He also said the state’s main witness, Mark Jackson, lied to police several times about the shooting and then made a deal to testify against Cannon.

David Dorn in his office

David Dorn, a retired police captain, was protecting a friend's pawn shop in June 2020 when he was shot and killed by looters. (Missouri Department of Public Safety)

Cannon did not testify during the three-day trial. Dorn retired from the St. Louis police in 2007 after 38 years. 

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He also served for six years as police chief in Moline Acres.

Fox News’ Michael Ruiz and The Associated Press contributed to this report.