By Joe Holden

PHILADELPHIA (CBS) — Philadelphia police sources confirm Keith Gibson has been taken into custody in connection to the murder of a Dunkin’ manager in the Fairhill section of the city over the weekend. Philadelphia homicide detectives tell Eyewitness News Reporter Joe Holden that Gibson has been labeled a serial killer.

He is the suspected gunman in the fatal shooting and robbery of 41-year-old Dunkin’ manager Christine Lugo.

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Police say Lugo was opening the Dunkin’ located on the 500 block of West Lehigh Avenue just before 5:30 a.m. Saturday when Gibson fatally shot her during a robbery. Coworkers tell CBS3 she was a mother of two with a “kind heart and smile.”

Officials say after the Dunkin’ shooting, he shot and critically wounded a 19-year-old in Wilmington and pistol-whipped a female worker at a Rite Aid in New Castle.

On Feb. 8, police say he killed his own mother at a location on Ridge Avenue and on May 15 officials say he killed a worker at a T-Mobile store in Elsmere, Delaware.

In 2008, he was convicted and served time for committing a homicide and commercial robbery in Delaware.

Wilmington police confirm Gibson was taken into custody Tuesday in connection with an armed robbery around 8:20 a.m. He was wearing a bulletproof vest and was armed with a knife and loaded gun.

He’s charged with first-degree robbery and is being held in Delaware.

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A revolver that is preliminarily believed to be connected to many of the shootings was recovered.