Security guard's death remains a mystery after suspects tried to rob him

HOUSTON, Texas (KTRK) -- There is new information about a security guard who was shot and killed by a robber in north Houston.

Robert Marquez apparently chased the criminals for four miles before he died.

A new memorial for Marquez has popped up along the 600 block of Rushcreek. He was gunned down last Saturday in a case that remains unsolved.

Houston police say Marquez, who runs a private security company, was patrolling the area around this townhome complex when someone allegedly tried to rob him.

Police say the robber took off after seeing Marquez's uniform, but he gave chase that came to a tragic end a few miles away, where shots were fired.

On Thursday, Marquez's best friend since middle school spoke on behalf of the family.

"Somebody knows something, and with that, if you know something, please share it. Because this time it was Robert, next time could be my family or yours," Steve Brown, Marquez's friend, said.

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