A veteran NYPD sergeant allegedly splashed semen on a civilian employee as she walked down a hallway at One Police Plaza, where they both work, sources told The Post on Tuesday.

The victim, an administrative aide in her 60s, had just left the women’s rest room and was walking back to her office when Sgt. Michael Iscenko, 54, allegedly approached her from behind and splashed the substance on her leg and shoe, the source said.

“She suddenly felt something on her leg, looked down, and said to him, ‘What are you doing?’ “ the source said of the January incident.

“The uniformed member then walked away without responding.”

The woman, whose name was not released, immediately complained to her superiors.

The substance on her leg was tested, and was confirmed to be semen, the source said.

The two are workplace acquaintances, the source said.

On Monday, the Manhattan DA’s Office obtained a warrant ordering the sergeant to provide a DNA sample so that a lab can determine if the substance is a match.

Iscenko, a divorcee from Long Island who is assigned to the Organized Crime Control Bureau, has been suspended.

One Police Plaza is thick with surveillance cameras, so at least part of the alleged attack was captured on video, the source said.

The woman’s body obscures the sergeant in part of the video; but he can be seen at one point crouching behind her, and at another point walking away .

He has not yet been criminally charged.

The NYPD’s Office of Equal Employment Opportunity is also investigating the incident, in consult with the DA’s office.

“Everyone who has been questioned says he looks very professional; he wears the uniform well,” the source said. “ This is not some creepy looking pervert. He’s entirely normal looking.”

The NYPD did not immediately comment.