PHILADELPHIA (CBS) ? Police say a 28-year-old woman was killed inside of a rooming house in Philadelphia Tuesday night, and her baby boy was found next to her body. The shooting happened on the 5400 block of Stewart Street in the city?s Overbrook section just after 8 p.m.

Witnesses tell police they only heard one shot ring out, and when officers walked into a second-floor bedroom, they discovered a woman with a gunshot wound near her mouth bleeding out.

Police say the woman was unresponsive. Officers had to carry her out of the home, where she was rushed to Lankenau Hospital. She was later pronounced dead.

Her 6-month-old son was still on the bed with blood on his clothing, police say. The baby was not injured but was taken to Children?s Hospital of Philadelphia to be checked out, according to police.

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Police say the victim only lived in the rooming home for a week or two, but witnesses tell police it all started with an argument between the victim and a man.

?We believe that the 6-month-old son is most likely in the room when the shooting took place,? Philadelphia Police Chief Inspector Scott Small said.

Police say the suspect took off running north on 55th Street. There is no motive for the shooting at this time.

Police say there were at least five other people in the rooming house at the time of the shooting, who are now being interviewed by detectives.