Cops have charged a 17-year-old with murder in the brazen Saturday shooting death of a beloved security guard at a Midtown subway station, police said Thursday.

The teen is accused of shooting Darrel Rodriguez, 26, in the chest on a crowded subway platform at Seventh Avenue and 53rd Street, fleeing the scene and leaving the victim mortally wounded.

Sources said the pair had some kind of dispute but did not know each other before the shooting.

Police said the accused killer turned himself in with his lawyer on Thursday, and is being charged with second-degree murder, criminal possession of a weapon and criminal possession of a loaded weapon.

Rodriguez, who manned the front desk as a security guard at a Manhattan building, lived in the Bronx and cared for his ailing father, according to neighbors and relatives said.

He was described as a “beautiful kid” in his neighborhood, and has two brothers, including a twin in the military who lives in Texas.