A neighbor said he is filled with guilt after hearing the cries of a 9-month-old boy who is believed to have starved to death in an apartment after his mother died of an apparent overdose. 'If I was closer to the noise, I would have done something. I didn't know. I feel so guilty. I feel so bad,' William Gonzalez said. The brother of the Pittsburgh-area woman went to check on his sister Friday morning , when he found her and her child, Casey, dead in their second floor home. Sara Kessler, 22, had not been heard from recently and may have died a week or two earlier, Assistant Allegheny County police Superintendent James Morton said. Scroll down for video . Sara Kessler (pictured) lived with her 9-month-old son Casey on the second floor of an apartment block in Millvale, Pennsylvania. They were found dead by her brother after he hadn't heard from her for several days . She was found on her bed and her son was in the living room. The superintendent said there were no signs of foul play. Mr Gonzalez, who lives on the first floor, said he was most upset knowing that the child was left alone with no chance to survive. 'The thought of that little kid running around after she died ... looking for food ... It's such a helpless feeling,' he told the Pittsburgh Tribune Review. 'It's a very sad situation in there,' Morton told reporters outside the apartment in Millvale, just across the Allegheny River from Pittsburgh. 'It seems like he [the infant] tried to survive but there was no food or anything for him to have.' 'It looked like he was trying to get around somehow by himself for who knows how long.' Pediatrician Dr Stephen Nelson said that the child may have survived a week without water. Sara Kessler's mother died of natural causes in the same apartment in November, Morton said. Gonalez and fellow tenant Elizabeth Freismuth said that the loss shook the young woman. Neighbor William Gonzalez said he feels guilty after hearing the cries of baby Casey following the death of his mother Sara (pictured) Kessler was known to be a drug addict by other residents of the building (pictured) and it is suspected that she died of an overdose. Casey's body was found in the living room - he is thought to have starved to death . 'She seemed so sad her mom was gone. I told her if she needed anything to ask me, but she never did,' Ms Freismuth said. 'Sara was a little on the wild side, but she was trying to be a good mother. She was devastated by my sister-in-law's death,' her aunt Kim Knaus said. Ms Freismuth added that Kessler 'loved that little baby. He was such a beautiful little boy'. Police suspect Kessler died of a drug overdose, and needles were found all over the apartment. A former resident of the building told CBS Pittsburgh that she was a drug addict and said that her family had tried to get her help many times. No one else lives on the same floor of the apartment building. Autopsies were scheduled for Saturday to officially determine the causes of death. Three house cats were also found in the second floor apartment. Police say the animals survived because of an automatic feeder, according to WPXI. Kessler's mother (pictured with Casey) had lived with her in the apartment until her death in November of natural causes .
Sara Kessler, 22, and son Casey, 9 months, were found by Sara's brother . Kessler died of a suspected drug overdose in apartment full of needles . A neighbor heard Casey's cries for days, but they were unanswered . Kessler's mother died of natural causes in the apartment in November . Three house cats survived due to an automatic feeder .