Cap’s DNA nails ‘perv’

A man’s Texas Longhorns cap flew off his head while he was trying to rape a woman outside a MetroNorth station in Westchester County, and cops used it to bust him for the crime — and a second sex attack, authorities said Monday.

Ronal Danillo Sandoval-Campos (inset), 24, was wearing the burnt-orange cap when he struck up a conversation with a 19-year-old woman and followed her onto a dirt path near a parking lot at Purdys station at 8 a.m. Aug. 21, according to MTA cops and Westchester police.

Sandoval-Campos, of Purdys, allegedly grabbed her from behind and groped her breasts and buttocks before she fell to the ground, sources said.

He allegedly held her down, but she fought him off, and he fled when a witness walked by the path, according to police sources.

They tracked him down to a nearby home the same day based on the woman’s description, a police source said.

Police took DNA from the suspect and his hat. The evidence linked him to the attempted rape — and a June rape in Mount Kisco, cops said.