LARGO — Police say the father whose 8-month-old was left in a bedroom with no air conditioning was told the day before the infant's death to keep his children in another room.

William Francis Hendrickson, 25, now faces charges after police found his son lifeless in a playpen on Thursday.

The bedroom at the S Belcher Road mobile home was 109 degrees when police arrived. The baby's body temperature was 105.6 degrees, and Hendrickson's daughter, 2, was sent to Johns Hopkins All Children's Hospital to be treated for dehydration, according to a police affidavit.

Police said they performed CPR on the boy until paramedics arrived, but he died at the scene. According to the Florida Department of Children and Families, his sister is in the care of relatives.

Meanwhile, the children's mother sat in a jail cell, arrested days earlier on a battery charge.

About 12:30 p.m. Thursday, Largo police officers responded to assist Pinellas County Child Protection investigators with a welfare check on the two children at the King's Manor Estates mobile home park at 1399 S Belcher Road, Lot 112.

Child services had told the father the day before not to leave the children in the bedroom, police said, but Hendrickson said he had "nowhere else to go" after his girlfriend was arrested the week before on charges she fought with his mother.

"He kept the children confined in the bedroom with him to avoid his live-in parents," police wrote.

Hendrickson faces charges of aggravated child neglect for the condition of his daughter and aggravated manslaughter in the death of his son, according to police. His bail is set at $150,000. He has had no arrests prior to Thursday in Florida, records show. During his first court appearance, Hendrickson said he worked as an Uber driver.

Sherry McCauley, 48, who lived next door, called the mobile home a "house of horrors."

She became fast friends with Carrie Hendrickson, but whenever she went over, she refused to sit on the furniture because it was dirty. Inside, it was hot and dark; the windows were always closed, and the curtains were pulled tight. There were cockroaches and bugs everywhere, she said.

"It was horrific," said McCauley, who moved back home to Pennsylvania in May. "From day one, I just got a creepy feeling about it."

She said she has heard Carrie Hendrickson's husband, Bill, talk about keeping the air conditioning off in order to keep it from burning out and running up the bill.

"He was very adamant on (the air conditioning) not running all the time," she said.

She said when she found out the infant had died, she was baffled. She knew Carrie Hendrickson loved her grandchildren.

"I feel bad for the entire family," McCauley said.

The children's mother, Elizabeth Michelle Rutenbeck, 24, was arrested July 22 on a misdemeanor charge of battery. According to an arrest report, Rutenbeck tried to force her way into Hendrickson's mother's bedroom in the mobile home.

"The defendant then pushed through the victim to get an Xbox from inside the victim's room," the report says.

Rutenbeck was booked into the Pinellas County Jail. Already on probation for felony charges of grand theft, she is being held without bail.

Two days later, Hendrickson's mother, Carrie Hendrickson, filed a domestic violence petition against Rutenbeck. She identified Rutenbeck as her son's "baby mama." In it, Carrie Hendrickson wrote that Rutenbeck injured her neck and knee and that a door she damaged needs to be replaced.

"All her belongings need to be removed from premises," she wrote.

On Friday about 10 a.m., detectives knocked on the mobile home's door. The woman who answered barked, "My grandson is dead because you did not do your job," before allowing them inside.

Dr. Charles Paidas, professor of surgery and pediatrics at the Morsani College of Medicine at the University of South Florida, said an infant is already predisposed to conducting heat from the environment at a greater level than adults. A fever for an infant is considered at or above 101.5, and as the temperature climbs, 106 and higher is considered critical thermal maximum. As the temperature climbs, the cells begin to secrete waste, and organs begin to fail. The brain also responds by going into a stupor, he said, which can lead to dizziness, headaches and confusion.

But infants are more susceptible than adults in shorter amounts of time, said Paidas, who also serves as medical director at the level 1 pediatric trauma center at Tampa General Hospital.

"A baby is going have the most dramatic response in the least amount of time," he said.

But at 109 degrees?

"That's impossible to survive."

The Hendrickson family was well known to child welfare investigators.

DCF said there had been three previous investigations because of concerns about the wellbeing of the children.

A social worker with Directions for Living was working with the family. The Pinellas nonprofit is subcontracted by Eckerd Kids, the lead agency for child welfare in Pinellas County.

Officials from Directions said they could not comment on the details of the case because the investigation is pending.

Eckerd Kids officials described the death as "heartbreaking" and said Directions had raised concerns about the children to "the proper authorities" but declined to elaborate.

Times senior researcher Caryn Baird and Times staff writers Samantha Putterman, Laura Morel and Chris O'Donnell contributed to this report.