Cue “Return of the Rat” – the furry fiends are back on First Street.

Last summer when the BMW Guggenheim Lab took over an empty lot between East First and Houston Streets, near Second Avenue, even the project’s detractors begrudgingly gave it credit for cleaning up a longstanding rat infestation. Well, guess what? The rats are back.

A friend who lives a couple doors over from the lot, which is now a park hosting public programming, brought the rodent resurgence to our attention. (She didn’t want to be named lest she gain a reputation on the block as, well, a rat.) “They’ve steadily become more of a presence and now it’s threatening to be what it used to be,” she said, adding that she has started walking in the street again to avoid the stretch of sidewalk on the southern side of First Street, near Second Avenue, where the whiskered interlopers frolic.

Sure enough, minutes after The Local set up to film the rats on a recent evening, they were seen zig-zagging across the sidewalk every 20 seconds or so, scampering from underneath a set of trash containers to a pile of garbage bags across the way. Passersby shrieked at the site of the voluminous vermin. Before long, we bumped into Emily Armstrong, co-author of The Local’s Nightclubbing column and a longtime resident of the Lower East Side. “They’re back!” she exclaimed as she walked her dog on the block.

Daniel Maurer Rat trap at First Park

Ms. Armstrong explained that as far back as a decade ago, her kids and their friends called the area “rat alley.” Writing for The Local, Tim Milk said “Rat City” went back 20 years.

At one point, a woman even fed the rats, said Ms. Armstrong, who also recalled seeing a mother inadvertently run one of them over with her baby stroller. “They scurry from that building to the curb and then back and forth. They go from the basement of the building to the garbage pails in front of the building to the bags on the curb,” she said, adding, “They were gone for a really long time. It did look like they had eradicated the rats, but they’re back.”

The super of a building on the block denied there was a rat problem, refusing to be named because he felt the topic was gossip. And Justin Luke, a member of First Street Green who occasionally organizes events in the lot, which is across from his Audio Visual Arts gallery, told The Local he hadn’t noticed any rats. “I’m sure there are rats over there but trust me, it’s nothing like it used to be,” he said.

Daniel Maurer A hole beneath a tree.

But our source on the block pointed to what seemed like rat holes in the flowerbeds of First Park, where we spotted several rat traps including the one pictured here.

“There’s no other place I can think of where you see rats pretty much 24/7, scurrying to wherever they live,” said Ms. Armstrong. “There’s something going on there. There has to be.”

Additional reporting by Melvin Felix.