A 25-year-old woman stopped a thief from escaping on an R train, police said. View Full Caption DNAinfo/Michael Ip

UNION SQUARE — A quick-thinking woman tracked down a thief who stole her wallet, chased him into the Union Square subway station and grappled with him to stop him from getting on a train, holding him until police arrived to arrest him, the NYPD said.

The 25-year-old woman had just finished eating at the Wendy's at 20 E. 14th St. about 3:50 p.m. on July 17 when she realized she had forgotten her wallet on the condiments counter, police said.

She immediately checked the Chase app on her phone and saw two unauthorized charges had just been made nearby, one for $109 at a Journeys shoe store and another for $46 at a liquor store, police said.

The woman raced over to the Journeys, at 28 E. 14th St., and spotted Cory White, 34, who had just finished paying for shoes and was also carrying a liquor store bag, police said.

When the woman confronted White, he dropped her credit card on the ground and took off running.

She chased him along 14th Street to the Union Square subway station, shouting for police to help her, the NYPD said.

White threw the woman's wallet at her and kept running, but she followed close behind as he ducked into the subway station, ran down to the southbound N/Q/R platform and tried to get on an R train, police said.

The woman struggled with White to stop him from getting on the train, and she hung on even after he elbowed her in the face and arm, police said.

Officers who had heard the woman's pleas for help intervened and arrested White.

Police found $93 in cash and the woman's MetroCard on White when they patted him down. Police also obtained surveillance video from Journeys showing White making purchases there, the NYPD said.

White was charged with robbery and grand larceny. His attorney did not immediately respond to a request for comment.

Other recent incidents in the 6th Precinct include:

► Two men were caught doing a marijuana deal in the playground inside Washington Square Park, police said.

William Bogart, 45, and George Washington, 51, were charged with criminal sale of marijuana after police saw them exchange a small object for cash at about 5:50 p.m. on Aug. 1, the NYPD said.

When police intervened, they spotted the marijuana, according to the police report.

Bogart and Washington had not been arraigned as of Wednesday. Information about their lawyers was not immediately available.

► A man's backpack was stolen while he was eating at the restaurant inside the Marlton Hotel on Eighth Street, police said.

The 28-year-old told police he left the black North Face backpack, which contained his laptop, in a corner of the restaurant at 9 p.m. on July 27 before sitting down to eat.

When he went to retrieve the backpack, it was gone, along with the laptop and a pair of tortoiseshell prescription Ray Ban sunglasses that were inside, police said. In all, the man lost $1,470 worth of items, police said.

► A woman's purse was stolen at Provacateur, the nightclub inside the Gansevoort Hotel, after she left it on the bar for about five minutes and forgot about it, she told police.

The 21-year-old victim, who set down her wallet about 9:40 p.m. on July 28, returned as soon as she realized what she had done, but her wallet was already gone, police said.

The woman lost her $200 iPhone 5S, and unauthorized charges were made on her credit card for $62 at Supreme Service and an unknown amount at Shell Oil at 117 Morningside Ave., police said.