Authorities charged a veteran NYPD detective with sexual abuse after he allegedly grabbed a female cop’s butt inside of police headquarters — a move that his lawyer blasted as “unjustified” and “inexplicable.” 

Det. Paul D’Amico, who has been with the department since 1996, was accused of groping the female officer just before 10:30 a.m. on Feb. 5 at 1 Police Plaza.

“I felt an individual squeeze my right buttocks with their hand,” according to a complaint filed with the Manhattan District Attorney’s Office. 

When the shocked woman turned around, she saw D’Amico, 51, was the “only individual in the area directly behind” her, according to the complaint. 

The second-grade detective allegedly said, “I’m sorry!” as he ran away. 

D’Amico was arrested on Thursday and charged with forcible touching and sexual abuse in the third degree, both misdemeanors. 

During his arraignment, a Manhattan criminal court judge ordered him released without bail but issued an order of protection to bar D’Amico from approaching the victim for the foreseeable future. 

D’Amico had been assigned to the NYPD’s Criminal Justice Bureau, where he chauffeured around head Chief Ruben Beltran when he allegedly grabbed the woman.

He was transferred to the NYPD’s Medical Division in March. 

“The decision here to charge him criminally is as unjustified as it is inexplicable. Det. D’Amico is a highly regarded 27-year veteran of the Department with a spotless record.

Yet the Manhattan DA has treated him like a common criminal,” James Moschella, a Detectives’ Endowment Association attorney, told The Post.