CHICAGO (CBS) — The heartbroken mother of murdered University of Chicago graduate Dennis Shaoxiong Zheng spoke Thursday during her son’s memorial service – in an emotional day on campus.

The memorial service for the recent statistics master’s graduate and aspiring data scientist was held at Rockefeller Memorial Chapel, 5850 S. Woodlawn Ave.

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Zheng, 24, was shot and killed during a robbery in broad daylight on Tuesday, Nov. 9, at 54th Place and Ellis Avenue – just half a block of north of where the U of C campus begins.

Dennis Shaoxiong Zheng

Dennis Shaoxiong Zheng (Credit: University of Chicago)

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Alton Spann, 18, has been charged with first-degree murder, armed robbery, and two counts of unlawful use of a weapon. Police said that it was all over a cellphone that was later sold for $100.

Since Zheng’s murder, Chicago Police and school leaders have tried to reassure students they will be safe.

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Chicago Police and University of Chicago Police will be working more jointly moving forward. A safety plan discussed Wednesday night entails live cameras from a new operations center soon set to open, and keeping campus police and students in the loop about crime in the area – as students have been demanding.

CBS 2 Chicago Staff