A couple who frequently baby-sat a toddler before she was beaten to death last year shifted the blame Friday back to the man charged with the crime.

Chad Evans, 30, faces second-degree murder and assault charges in the November 2000 death of his girlfriend’s daughter, 21-month-old Kassidy Bortner.

But Evans’ defense lawyers – with help from the baby’s mother – have argued the real killer was Jeffrey Marshall, the last person to see Kassidy alive.

Marshall and his girlfriend, Jennifer Conley, often watched Kassidy at their Kittery, Maine, home in the month before her death. Kassidy’s mother, Amanda Bortner, is Conley’s sister.

Bortner testified earlier this week that Kassidy sometimes returned home with suspicious bruises, but both Marshall and Conley said it was the other way around: Kassidy often would arrive at their home with strange injuries.

Conley, 21, said she asked her sister why she needed her to baby-sit so often, and was told that she was worried another baby sitter would notice the bruises and the child could be taken away from her.

Over time, Kassidy became withdrawn and quiet, Conley said, but was affectionate with Marshall.

“She was happy around Jeff,” Conley said. “She was not reluctant to be around him.”

In contrast, Evans called the baby “a little b–, a retard, stupid,” Conley said.

Under cross-examination, Conley described phone calls Marshall made to her the day Kassidy died. The defense has argued Marshall put off calling an ambulance.

After calling once to say the girl’s eyes were rolling back into her head, Marshall called back to say she was “coming around,” Conley said.

Conley later told police that Kassidy was alert and watching television. Asked why she said that, Conley said “I assumed that” from what Marshall told her in the second phone call.

Asked why she didn’t tell police that was not correct, she said she didn’t remember what she told police.

“I told them what I thought they wanted to know,” she said.

“You told them what they wanted to know?” defense lawyer Mark Sisti asked. “Are you telling the jury what they want to know?” Marshall, who opened Friday’s testimony, repeated his earlier statements that he never harmed Kassidy.

“I never saw her [get] hurt at our house,” he said. “I didn’t mind taking care of her. I loved Kassidy.”

Also Friday, Bortner’s brother, Joshua Bortner Conley, testified that he noticed bruises on Kassidy in September, about two months before her death.

“I asked [Amanda] what the heck was going on,” said Conley, 16, who also babysat Kassidy.

He said Bortner told him Kassidy had fallen off a trampoline. He also said the baby seemed reluctant to go home with Bortner after visiting him and his mother.

In the days after the toddler’s death, Bortner told police Evans had been abusing her daughter for more than a month.

But she later balked at testifying against him, and agreed only after being charged with child endangerment and being offered immunity for anything she says on the stand. At the trial, she has backed off her earlier claims and implicated Marshall.

Bortner, 19, and Evans were living together when Kassidy died, and lived together for about nine months afterward, in violation of a court order.