BOSTON -- Investigators worked with witnesses Tuesday to try to find the person responsible of a fatal stabbing that left an 18-year-old CVS Pharmacy store clerk dead.

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Kelley Tuthill Reports On Investigation

NewsCenter 5's Kelley Tuthill reported that Christian Giambrone, of Jamaica Plain, was stabbed to death, and another employee was injured outside the store on Brookline Avenue when they tried to apprehend a shoplifter Monday night.

"There is a whole area of dedicated medical professionals around here that take care of people that are injured, and to have that happen right on our front door steps is just appalling," said Dr. John Maurice, who works in the area.

"I saw this black guy stealing. He had a bunch of stuff inside his jacket. He had a red jacket," one witness said.

The witness told the CVS manager what she saw. He and another employee chased the alleged shoplifter outside. The man allegedly pulled out a knife.

"They left the store and confronted this individual on the sidewalk. The suspect stabbed both of the men," Boston Police Department spokeswoman Mariellen Burns said.

The suspect entered the Shapiro Clinical Center, which is attached to the Beth Israel Deaconess Medical Center. Police scoured the halls, but only found his coat and hat.

Witness Willard Massie tried to help the victims.

"I gave him my head piece to put on there to hold pressure. He stopped breathing, so I did chest compressions on him and he came back. So, he was breathing again. By that time the ambulance had gotten here, and they carted him off," Massie said.

The 32-year-old victim was listed in stable condition a local hospital.

CVS has offered a $25,000 reward for information on the case.