The mother of an 18-month-old girl beaten to death in her family’s squalid Chester apartment was charged with first-degree murder and related crimes Tuesday, along with her boyfriend, who faces the same charges, authorities said.

The arrests of Kandie A. Meinhart and Maurice Eugene Davis come more than five months after the January death of Li’Aziah Thomas, and a month after Meinhart appeared on the nationally televised “Steve Wilkos Show” to profess her innocence. During the show, Wilkos told the audience Meinhart had passed a polygraph.

Meinhart, 31, and Davis, 29, face charges of first- and third-degree murder, involuntary manslaughter, child endangerment, conspiracy, and related crimes.

Both are being held without bail at the Delaware County Prison.

Meinhart called 911 after she said a sibling found the child unresponsive in her crib. The Medical Examiner’s Office said the child died of blunt-force trauma and severe blood loss, and ruled the death a homicide.

“The facts of this case are truly horrific: a mother and her boyfriend are literally responsible for beating to death this defenseless baby,” Delaware County District Attorney Jack Stollsteimer said in a statement Tuesday. “Our investigation found that baby Li’Aziah suffered multiple blunt force injuries during her last night of life from the very people who are supposed to protect her.

“While we are horrified this crime could happen in our community,” he said, “I am thankful that because of the dedicated work of detectives and prosecutors, we will be able to bring her killers to justice.”

In a brief phone interview in February, Meinhart, a fast-food manager, said she was not home when herdaughter died, and she didn’t know what happened to her. “I was at work. I came home, I went to sleep and I found her the next morning. Well, my daughter carried her to me the next morning,” said Meinhart, who has three older children.

The child’s father, Anthony Thomas, and his mother, Michele Rice, who had pressed authorities on the progress of their investigation, said Tuesday they were grateful to learn of the arrests.

“I’m actually feeling good it finally happened,” said Thomas. “

“I’m happy that there’s almost an ending, but none of this brings my baby back to me,” said Rice, who noted that Li’Aziah would have turned 2 on July 5, the day after her own birthday. “She was my birthday gift.”

The family’s attorney, A.J. Thomson of the Center City firm of Edelstein Law LLP, who had worked with the family to draw law enforcement attention to the case, called the child’s death

“the worst crime imaginable.”