NEW YORK — A missing 2-year-old boy is now feared dead after police say he may have been thrown in the Bronx River by his father.

Detectives have reason to believe the 20-year-old father of little Montrell Williams threw him into the river, near the Bruckner Expressway.

NYPD divers have been focusing their search under the expressway as investigators have surveillance video of the father with his child along the river.

Detectives reportedly have surveillance video showing Montrell’s father throwing a black bag into the river.

The child’s family has been walking up and down the river doing their own search, clinging on to hope.

Montrell Williams vanished on May 9 after a custodial visit with his father. The next day, on May 10, the child’s father and grandmother, with whom he was living with, had a fight. Officials believe the father left with the toddler and was never returned to the child’s mother.

“Me and him had a conflict. I’m in my room. My cousin told me that my son took the baby. I went downstairs to chase him. He was gone. From that day, I was trying to search for my grandson,” the grandmother said.

Then, almost a month later on Sunday, June 8, the missing child’s 17-year-old mother says she saw the father and confronted him.

He reportedly responded by pulling a knife. But the haunting words he used proved far more cutting.

The father allegedly claimed he threw his own child into the river, prompting the teenage mother to call the police.

The police were called, and when he was pressed about his son’s whereabouts, police said the father’s answers sent up major red flags.

Montrell’s grandmother, the father’s mother, has been desperately searching for Montrell for a month.

“I just hope my son opens his mouth and speaks. I love him and bring my grand baby back,” the grandmother said.

Montrell’s grandmother says she went to the police the day after that argument in May, a month ago.

“I went to the precinct. They didn’t help me,” she said.

“We’re still unraveling exactly what happened. Were proper procedures followed?” NYC Mayor Eric Adams said on Tuesday when asked why it took so long for police to file a missing persons report.

“We’re still investigating all actions. The actions of the dad, the actions of officers who responded. And once we have a full understanding based on the detectives division, we’ll be able to answer what happened, but right now our goal is to find the child,” Adams said.

The father appeared in Bronx Family Court on Monday to answer a warrant for failing to return the boy to the mother, per their custody agreement.

Montrell’s father was put in jail by a judge after he failed to disclose the child’s whereabouts.

The 20-year-old father has not yet been criminally charged. Authorities say he has refused to tell detectives and family court what happened to his toddler.

Police do not believe the mother, who is 17, knows where their son is.

Neighbors say they are shocked he hasn’t been seen in nearly a month.

“I can only imagine what his mom is going through right now,” said the boy’s neighbor, Tracey Pringle. “The only thing we can do is just hope and pray that he’s OK and that he’s returned safely.”

The missing toddler is described as having a medium complexion, brown eyes and black hair. He was last seen wearing a white shirt and a diaper.

Anyone with information regarding this incident is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).