Rolex watches are the goal of grifters and hookers searching for boozy victims in nightclubs and bars. View Full Caption The Image Gate/Getty Images

MANHATTAN — Police fear a summer wave of thieves who target boozy nightcrawlers wearing high-end Rolex watches in nightclubs, bars and hotels after a rash of similar crimes last year, DNAinfo New York has learned.

In 2014, the city saw a number of thieves — allegedly armed with date rape “Roofies” — targeting fun-seekers sporting expensive Rolex watches and other valuables that they can steal, according to law enforcement sources.

“New York is where the money is, and the working girls and guys do the circuit, and when it gets warm they come back here,” a source explained. “They follow the money, and the Rolex is big.”

About two-dozen such thefts were reported last year, sources said, though that number is likely low, because the victims of such crimes rarely go to the police because they were caught in compromising situations.

Take the case of the 24-year-old Gramercy Park man who picked up two women at Tao on East 58th Street last June 1. He brought the duo to his apartment on E. 19th Street, where they headed into the shower together, emerged semi-naked and prepared a drink for him.

That was the last thing he remembered before he woke up in the morning with the girls missing — along with his iPhone, Apple laptop and Rolex.

And then there's the 43-year-old man who met two women at the Gansevoort Hotel, had a few drinks and then took them home to West 71st Street, where he woke up to the sound of his guest departing — with his credit cards, wallet, laptop and Rolex.

And then there was the 35-year-old man out clubbing last July 1. He met a woman at a bar who escorted him to the Marriott Hotel on Broadway.

Before he went to sleep, the “lucky” reveler put all his valuables in the room's safe. But the following morning, when he woke up alone, he tried to open the safe, but could not. His guest had apparently watched him lock his property and memorized the secret code.

Security guards were needed to open the now-empty vault, which no longer had the victim's credit cards and two luxury watches, including a Rolex worth tens of thousands of dollars.

“It does not matter if the victim is a polished guy looking for fast times, or just some well-heeled computer geek,” the source continued. “These criminals are like travelers, and grifters and professional working girls.

"They don't hang around long to avoid being too familiar and easy for the police to find," the source continued. “They chart certain events, and know when to come around, and I can assure you we are not talking about being in Washington for the Police National Convention.”

Although the NYPD's various Hotel, Vice, and Grand Larceny squads are aware last year's crimes and fear a new wave this summer, there is little they can do to prevent it. Overly aggressive tactics are shunned by the hotels and clubs that are most vulnerable, another law enforcement source added added.

Victims in these sorts of cases often have their losses covered by insurance, and hotels encourage victims not to report the incident by offering free stays.

When the NYPD does catch the occasional crook, detectives invariably determine that their cell phones have area codes that reflect their true home base — generally warm-weather states such as Florida, Texas, Arizona and California. And they generally receive a slap on the wrist, and head out of town.