Police say the man struck four times in just three weeks in the Bronx and Manhattan. Now, authorities have released images of the suspect and are warning residents to be on high alert.
Three of the incidents happened around Co-Op City in the Bronx, while the most recent incident, which occurred just last week, happened in Peter Cooper Village in Manhattan.
Police say the man follows women into elevators and then threatens them with a knife or ice pick before stealing cell phones, jewelry, shopping bags and cash.
"We just know to be more careful," Bronx resident Leilani Soto said. "Everyone was notified to be more careful. Not be alone, especially if you're a female in the elevator at night, because that's what we were told, that it's happened late night, usually, catches you in the elevator."
Police have posted wanted signs throughout Co-Op City, hoping someone will take a second glance, recognize the thief and turn him in.
He is described as being in his 40s, about 6-foot tall and 250 pounds, with a close-cut beard and a green jacket.
Police ask anyone with information about the suspect to call Crime Stoppers at 800-577-TIPS.
You can also submit your tips by logging onto Crime Stoppers website at NYPDCrimeStoppers.com or by texting your tips to CRIMES (274637), and then entering TIP577.
All calls are strictly confidential.