CHICAGO (CBS) — An 18-year-old suspect has been charged in the murder of University of Chicago graduate Dennis Shaoxiong Zheng this week.

Chicago Police Supt. David Brown announced Friday that Alton Spann has been charged with first-degree murder, armed robbery, and two counts of unlawful use of a weapon.

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Alton Spann

Alton Spann (Credit: Chicago Police)

Police said Friday that it was all over a cellphone that was later sold for $100.

Zheng, 24 – who received a masters degree in statistics from the U of C – was shot during a robbery at 54th Place and Ellis Avenue on Tuesday afternoon just before 2 p.m.

Dennis Shaoxiong Zheng

Dennis Shaoxiong Zheng (Credit: University of Chicago)

As CBS 2’s Marie Saavedra reported, a memorial to Zheng at the site where he was murdered has been growing ever since Tuesday – but something new was added Friday. Spann’s name and the charges against him were printed out on paper, and underneath, someone wrote in purple marker: “Good job, Chicago Police! There is justice!”

Dennis Zheng Memorial

(Credit: CBS 2)

Chicago Police Deputy Chief Rahman Muhammad said Zheng was walking home from a class when Spann came up, announced a robbery at gunpoint, and shot Zheng in the torso. Spann then took Zheng’s personal belongings – including electronics, Muhammad said.

“The victim did nothing, at all, to deserve being shot and killed – at all,” Brown said. “Whether he was struggled, or startled, or said something back, he did nothing to provoke this heinous crime.”

Spann was then seen entering a running black Ford Mustang that was headed west on 54th Place. Area One detectives spotted the Ford Mustang – and Spann getting in – on POD cameras, private cameras, and University of Chicago cameras, Muhammad said.

Police determined based on the license plate that the Ford Mustang had been reported stolen from south suburban Markham on Wednesday, Nov. 3. The license plate helped lead police to Spann.

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On Wednesday around 6:20 p.m., Spann was tracked down near North Avenue and Sedgwick Street in the Marshall Field Homes development in Old Town. He had two guns and the key fob for the Ford Mustang, Muhammad said.

Another video showed Spann driving the Mustang to a cellphone store and going in to sell Zheng’s personal items for about $100, Muhammad said. The items were recovered by detectives.

“Just let that sink in,” said Supt. Brown. “A hundred dollars for Mr. Zheng and his family’s grief.”

When he was arrested, Spann was also wearing the same clothes he was in at the time of the shooting, police said. Muhammad said one of the two weapons Spann had with him matched what was used to kill Zheng in broad daylight.

“This case was solved through video cameras and license plate readers,” Brown said.

Police said Spann does not have priors offenses on his record as an adult, but he is only 18.

“We want not only for Mr. Spann to have significant consequence to the furthest extent to the law allows so that we can send a message to like-minded offenders,” Brown said.

A spokesperson for Mayor Lori Lightfoot released this statement late Friday:

“Mayor Lightfoot is extremely proud of the dogged and phenomenal work of the Chicago Police Department’s Bureau of Detectives to quickly apprehend and charge Alton Spann for the murder of Shaoxiong Zheng. Individuals who commit senseless and cowardly acts of violence, and who recklessly cut short the lives of residents must be held accountable, and it is the Mayor’s hope that this announcement can serve as the first step on the long road toward healing and justice for Mr. Zheng’s family and loved ones, as well as the University of Chicago Community.

“The Mayor will continue to keep this young man’s family, as well as the entire Hyde Park and University of Chicago communities in her prayers as they continue to grapple with this tragic loss. As communities throughout Chicago continue to struggle with gun violence, protecting the lives and wellbeing of all of Chicago’s residents and visitors remains the Mayor’s top priority.”

On Thursday, the University of Chicago announced an expanded safety plan. Shuttle bus service has been expanded, and students can also now get free Lyft rides through the day before Thanksgiving – Wednesday, Nov. 24.

Meanwhile, in addition to the patrols, CPD pod cameras – which allow for live monitoring – are also going up in the area. And to ease some international students’ worries, the university made clear there is no racial motive connected to the murder of 24-year-old recent recipient of a master’s degree in statistics.

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Brown said there are still some “loose ends” to tie up in the investigation, but he was not specific. Possible additional outcomes are charges against a getaway driver, Saavedra reported.

Marie Saavedra