Five adults were killed across two boroughs in three separate incidents on Wednesday, according to police, who also found a dead newborn baby behind a building in the Bronx.

The bloodshed began just before 8 a.m. in Ocean Hill, Brooklyn, where 34-year-old Kelvin Reynoso was stabbed to death near Atlantic Avenue and Monaco Place, officials said.

Police later arrested 29-year-old Devon Elliott, charging him with murder and criminal possession of a weapon. NYPD officials said both men lived in the same building on Atlantic Avenue, but they were not sure yet about a possible motive for the killing.

Four blocks away, on Atlantic Avenue and Marconi Place around 11:15 a.m., Ralph Hand, 35, was stabbed in the right arm and slashed on the right side of his head, according to police. First responders took him to NYC Health and Hospitals/Kings County, where he was pronounced dead.

Officials said the stabbing followed a verbal dispute that escalated and police did not make any immediate arrests or have any description of a possible suspect. Police were investigating whether the two incidents could be related, but so far have found no evidence suggesting a connection.

The 73rd precinct, which includes Brownsville and Ocean Hill, has reported 10 more murders this year compared to the same time last year, according to the NYPD’s CompStat database – even as murders continue to trend down overall citywide. That tally does not include Wednesday's incidents.

The rest of the violence took place around 8:15 p.m. during a single incident in the Longwood section of the Bronx – less than a mile from where 18-year-old Joshua Sparrow was shot and killed on Monday.

Police responded to a 911 call at a three-story home on Southern Boulevard and Avenue St. John, where three people were shot: a 34-year-old man, a 57-year-old woman, and a 57-year-old man. Both 57-year-olds were pronounced dead at the scene by EMS, according to police officials. The 34-year-old man was taken to NYC Health and Hospitals/Lincoln, where he was pronounced dead.

Police did not immediately release the names of the victims, and did not have any information about a suspect or motive. Police also did not have information about whether the victims were related to each other.

The 41st precinct, which includes the neighborhoods of Hunts Point and Longwood, has experienced significant declines in both shootings and homicides so far this year, according to CompStat.

Besides the killings, police discovered a dead newborn baby Wednesday morning behind a building on St. Lawrence Avenue and Gleason Avenue in the Soundview section of the Bronx.

NYPD officials said the baby appeared to be a girl with the umbilical cord still attached, though the Medical Examiner was working to determine exactly how the baby died. Police did not make any immediate arrests.

This is a developing story based on information from police and may be updated.