NEW YORK — Police are looking for answers in the death of a baby found floating in the East River in an area popular with tourists near the Brooklyn Bridge and the South Street Seaport.

Officials want to know: How long was the boy in the water before an Oklahoma family spotted him Sunday afternoon? Why was he wearing only a diaper? Where are the adults who were supposed to be caring for him?

A medical examiner will determine how the boy, about 8 months old, died. Police say he showed no signs of trauma.

Diana Campbell, of Stillwater, Oklahoma, first noticed the baby around 4 p.m. Sunday. Her husband, Monte Campbell, waded into shallow water near the Manhattan shoreline, retrieved the baby and started CPR.

“She just called me over and said there was a baby in the water,” Monte Campbell said. “I called 911. At that point, I thought it was a doll.”

He said the baby wasn’t breathing and showed no pulse.

Police officers arrived minutes later and took the baby onto the pedestrian walkway, where they continued CPR before the baby was taken to a hospital and pronounced dead.

No parent or guardian was present at the scene, police said.

The East River running between Manhattan and Brooklyn is a heavily trafficked tidal estuary subject to strong currents. Both park-lined shorelines are usually teeming with tourists this time of year.