The child's aunt also said she heard an argument between Burns and her live-in boyfriend, Jeffrey Daniels, earlier that night.
When police went to go question Burns about her child, they discovered she had been murdered.
"Officers entered Ms. Burns' apartment to conduct a welfare check and found her deceased," said Bergen County Prosecutor Mike Musella in a statement.
"She had been stabbed in the neck with a kitchen knife. The Dumont Police Department then notified the Bergen County Prosecutor's Office Major Crimes Unit and Bergen County Sheriff's Department Bureau of Criminal Investigations."
Per the news outlet, a neighbor claimed there was "constant friction" between Burns and Daniels.
Authorities responded to a call that Daniels had knocked on a nearby resident's door with two children and when police found him, Daniels was with Burns' other two children, ages 18 months and 6 months.
Daniels was arrested and charged with murder, possession of a weapon for unlawful purposes, and endangering the welfare of a child.