A Manhattan woman has been charged with second-degree murder after her 1-year-old son appeared to be fatally smothered inside a Midtown burger restaurant Monday afternoon.

Latisha Fisher, 35, of the Lower East Side, was found with the toddler, Gavriel Ortiz-Fisher, inside the bathroom of the 5 Boro Burger restaurant on 36th Street, near Sixth Avenue, after an employee realized she had been in there for a long time, police said. 

Several people had tried to use the bathroom and couldn't, police said, so employees jimmied open the door. Gavriel, who was foaming at the nose and mouth, was found in his mother's lap. 

He was taken to Bellevue Hospital Center where he was pronounced dead. Fisher was taken into police custody immediately following.

Fisher was awaiting arraignment Tuesday and could not be reached for comment.

Mayor Bill de Blasio said there didn't appear to be any history between Fisher and the Administration for Children's Services. He said this case appears to be one in which mental health was an underlying cause.

This is a horrible, horrible tragedy," de Blasio said, speaking at an unrelated news conference. "And this one – as a human being and as a parent – this one grabs at me as just profoundly troubling."

In 2012 Fisher pleaded guilty to second-degree assault and first-degree attempted assault for attacking a relative with a steak knife before tasing them in September 2011, according to court records. As part of her guilty plea, Fisher was required to complete two years of treatment with CASES Nathaniel Act Project, an alternative-to-incarceration program for certain defendants with mental illnesses.

She had several other prior arrests as well, but those are sealed, police said.

Marcus Comeau said he was standing down the block when he saw police leading Fisher off in handcuffs. He said Gavriel was being wheeled out with a mask covering his face.

"The mother was coming out in handcuffs," he said. "She didn't seem too distressed, kind of had her head down.

"She didn't make a lot of noise," he added. "Not a big fit."

Fisher, who was known around her Lower East Side apartment as “Honey,” was also widely known to have mental health issues.

“One day she’d say ‘hi’ to you, one day she doesn't," said Rafael Brenes, 53, adding he would often see Gavriel with his father. “It seemed like a happy baby. The baby was well taken care of.”

Fisher had a reputation of being volatile. Neighbors spoke about a violent incident years ago involving her and her family.

“She’s had problems in the past,” said Carolyn Lawson, 47, who also lives in the building. “It’s really sad, I don’t understand it."