Martzen spent a good deal of her pregnancy in a green jail uniform, accused of killing 17-month-old Ella Van Leeuwen while babysitting. The little girl suffered a fractured skull.
Martzen told neighbors Ella fell off the bed, but coroners ruled the injuries were much worse than an accident could have caused.
Now, Martzen is a new mother -- out of jail on a $2 million bail -- and CPS is investigating whether her baby boy is in danger.
"Our primary concern is 'Will this child be in any risk?'" said CPS director Catherine Huerta. "Our responsibility is to be able to say 'No.'"
The Van Leeuwen family rarely speaks publicly, but Ella's father gave Action News a statement.
"My family and I are very sad that another innocent child has been brought into this horrible situation. Our prayers go out to baby Maverick Martzen," he said.
Martzen has a big group of supporters who've raised about $50,000 for her defense fund. They're also willing to help raise the child, if necessary.
"The people who know her, there's a lot of support and they're kind of not sure what's going to happen," said her defense attorney Jeff Hammerschmidt. "But they're there for her and they're there to support [her husband] Scott and they're there to support the baby and whatever needs to be done to do that, they're willing to do that."
It's a rare case for CPS when a baby is born to a murder suspect -- someone who hasn't been convicted of a crime and is awaiting trial.
Investigators showed up at the hospital less than six hours after Martzen gave birth, but it wouldn't be unprecedented for them to allow Martzen access to her child in some capacity.
"We've had cases in which parents have admitted to violent acts against children and maybe not gone through a court process and not gotten convicted in which the circumstances when they gave birth to a new child are different and with a safety plan they could be allowed to keep the child," said Huerta.
Martzen's family and her attorney will meet with CPS again Thursday afternoon. She'll be on speaker phone from the hospital. They're expecting some sort of decision at that meeting. Her murder trial should take place early next year. The Van Leeuwens say that's when the truth will come out.