Prosecutors and defense attorneys presented their closing arguments Tuesday in the first-degree murder trial of 22-year-old Justin Marshall.

Johnson County prosecutor Janet Lyness approached the jury first. She deplored the slaying of Iowa City landlord John Versypt, 64, who died of a gunshot wound to the head in October 2009.

“This is a case about a robbery gone wrong,” Lyness said. “This is a case about a man who died, who shouldn’t have died.”

Alleging that Marshall was one of three men involved in the homicide, the prosecution also said Marshall was the one who pulled the trigger.

After listing key points outlined by each witness, Lyness reminded the jury the case is not an episode of television series “CSI” and noted there isn’t always an abundance of physical evidence.

“This is not TV,” she said. “This is real life.”

Gunshot residue found on Marshall’s jacket was one of the only pieces of scientific evidence linking him to the crime.

Lyness further argued Marshall’s story changed numerous times during interviews conducted by investigators days after Versypt’s death.

“Nothing in the defendant’s version fits the evidence,” she said, referring to various testimonies heard by jurors over recent weeks.

In his testimony, former suspect Charles Thompson said Marshall changed and discarded his clothing after Versypt’s body was discovered.

Lyness also cited testimonies from three inmates — Earl Freeman, Antonio Martin, and Carl Johnson Jr. — who were incarcerated with Marshall in the Muscatine County Jail.

In these testimonies, the inmates said Marshall admitted his guilt in the slaying of Versypt. Marshall told the inmates he was trying to lessen his sentence, Lyness said.

Thomas Gaul, Marshall’s attorney, began his closing argument by pointing out the lack of physical evidence against Marshall, and he suggested there is more evidence against Thompson.

“As far as physical evidence … nothing the state has produced points in Justin Marshall’s direction,” he said. “It does point in Charles Thompson’s direction.”

After that, Gaul questioned the legitimacy of the three inmates who said Marshall confessed to killing Versypt.

Calling them “longtime career criminals” and “snitches,” Gaul said the inmates had incentives for testifying against Marshall.

Gaul argued that Freeman, Martin, and Johnson testified in hopes of shaving years from their sentences.

“They’re old pros,” he said, claiming the inmates knew how to work the legal system.

When Lyness reapproached the jury, she insisted the inmates’ testimonies were reliable.

“What they told you makes sense and is consistent with other evidence,” she said.

Following the closing arguments, Judge Sean McPartland retired the jury to begin deliberating the case. The jury deliberated until 4:30 p.m., and it will return today.