William Gonzalez is haunted by the cries of a 9-month-old boy who, with no one to feed or care for him, died alone near the body of his mother inside their Millvale apartment.

Sara Elaine Kessler, 22, probably died in bed more than a week ago in the apartment on the second floor of the Chrismar Apartments building on Butler Street, said James Morton, Allegheny County Police assistant superintendent.

Her son, Casey Kessler, died on the living room floor sometime later, Morton said. Kessler and the baby lived alone, and the other second-floor apartments are vacant, Morton said.

"This baby seemed like he was struggling because there was no source of food or anything," Morton said. "There is no sign of foul play, nothing suspicious."

Morton would not speculate on how the woman died, but relatives said they were told by county homicide detectives that she could have died from a drug overdose or a medical problem. Autopsies are scheduled Saturday.

"What hurts me most is that I heard him crying," said Gonzalez, who lives on the first floor and heard the little boy's cries when he went in and out of the front door of the building.

"If I was closer to the noise, I would have done something. I didn't know. I feel so guilty. I feel so bad," said Gonzalez, whose apartment is around the corner and down the hall from the front door. "The thought of that little kid running around after she died ... looking for food. That's what I'm upset about. It's such a helpless feeling."

Dr. Stephen Nelson, a pediatrician who teaches at the Tulane School of Medicine in New Orleans, said the child probably died of dehydration.

It generally takes three to four weeks to starve to death. But someone can die within a week without water, Nelson said.

"It's the dehydration that kills you," he said. He "probably survived at least three to five days, maybe up to a week."

A brother, Matt Knaus, found the bodies when he went to check on his sister and nephew, Morton said. Knaus did not want to talk to the media Friday night.

Kessler and her son lived alone in the apartment since the death of her mother, Donna Knaus, 54, neighbors and relatives said.

Donna Knaus died inside the apartment Nov. 14 from a seizure disorder, the Allegheny County Medical Examiner's Office said.

"She was a momma's girl. Her momma looked after her," said Sara's aunt, Kim Knaus of McCandless. "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."

Gonzalez and another building resident, Elizabeth Freismuth, agreed that Kessler was struggling to cope.

"She seemed so sad her mom was gone. I told her if she needed anything to ask me, but she never did," Freismuth said. "She loved that little baby. He was such a beautiful little boy. She told me, 'I can't believe he's going to be almost a year old. He's getting so big.' "

Kim Knaus called Casey "a cutie. Sara was doing a good job of raising him. She was a good mother, very attentive."

Dottie Knaus, who is Kim Knaus' daughter, said her cousin "was a good-hearted girl, a good person, trying her (darnedest) to raise the child alone."

Casey, she said, "was so adorable ... . He was beginning to crawl around like a little man."

Dottie Knaus said she was angry at comments made by strangers on social media after hearing media reports that her cousin may have died of an overdose.

"We were assured by county detectives that it's not 100 percent how she died. We were told it could have been an overdose, it could have been some health problem," Knaus said.

She was upset that no one in the building who heard Casey crying called police.

"The baby was screaming for two days. The baby could have been saved."

Property records show the apartment building is owned by Lloyd Boys Properties, based in Westmoreland County. The company could not be reached for comment.

Neighbors were universal in expressing shock and sadness, saying they would have done something had they heard the baby crying for days.

"I hate to see kids suffer. I just wish someone could have done something for the baby," Steven Sansonetti said.

James Ralston called Kessler "a nice lady. She was respected by everybody. The landlord said she was a private person. She didn't socialize. She didn't cause no trouble."

Janet Stewart, 61, said Kessler and her son lived in the building for about six months, maybe longer.

"She was a very nice person," Stewart said. "She was a very good mother from what I saw."

The boy was learning to walk, and his mother would often take him outside to play.

"She loved that baby," Stewart said. "She definitely loved that baby."

Stewart said that Kessler was outgoing and friendly and her son was full of energy.

"He was a happy baby," she said.

Another neighbor, Nancy Coban, 73, said she was devastated when a neighbor told her the news.

"It's awful that no one found her," Coban said. "It's just a sad thing."