The "person of interest" - described as a gang member in her twenties - would have been involved in the Brooklyn incident, which reportedly saw sun-bathed policemen near 1400 East New York Ave.
Authorities were still looking for the suspect at 8:30 pm Tuesday, according to sources.
The New York police are trying to confront several other people in connection with the dump videos, which sparked outrage over the weekend.
One of the clips was filmed in the 28th district of Harlem, where uniformed officers were drenched Sunday night while trying to get arrested. The Brownsville incident would have occurred in the same way.
"They were reacting there, facing an incident. As they walked away, someone thought it was okay to take a bucket of water and throw it over a policeman's head, "said the NYPD.
The NYPD has asked for public help to identify the people involved. The officials promised to bring them to justice.