In Brooklyn, 33 people who were suspected of overdosing on K2 — a synthetic drug — were transported to hospitals on Tuesday.  New York City police raided five bodegas in Brooklyn on Wednesday, a day after a wave of suspected overdoses from the synthetic drug K2 sent at least 33 people to the hospital and raised fears that the use of a substance that officials had indicated was on the wane was instead on the rise.  The police found no K2, the synthetic chemical drug meant to mimic marijuana — which is illegal in New York State — in any of their raids, James Byrne, a spokesman for the Police Department, said. People at three stores, including the Big Boy Deli on Broadway, were arrested on charges of selling improperly taxed cigarettes, Mr. Byrne said.  The raids were just one reverberation from the localized public health emergency, which unfolded in several square blocks around an intersection on the border of the Bedford-Stuyvesant and Bushwick neighborhoods.  On Wednesday, there were few signs in the area that the crisis had abated at the bustling intersection. Near where emergency workers found the first eight people on Tuesday, a shoeless man sat on a stump staring into space, a “No Smoking K2” sign behind him. He got up and muttered as he walked down the block.  Around the corner, a man rocked back in forth in the morning breeze, a hand-rolled cigarette burning between his fingers. On Myrtle Avenue, two people sat on the sidewalk in a stupor, as one folded over on herself, while the other struggled to keep his eyes open. Two ambulances were parked in the area.  “It moves from neighborhood to neighborhood,” said Kimbell Frazer, a supervisor at the nonprofit Bowery Mission, as he helped to hand out sandwiches and apples to people in the area around Myrtle Avenue JMZ subway station, where a group of people had been found yesterday in varying states of stupor. “It never stops in one place for too long.”  Mr. Frazer said that in the winter, K2 had been a problem around the Bowery Mission, which serves homeless people in Lower Manhattan, before its leaders changed their policies to cut down the traffic of people outside.  “It’s a real epidemic,” Mr. Frazer said.  Standing nearby, Calvin Williams, 50, who said he had used K2 for 10 years, spoke about its appeal.  “K2 is like an elucidating high,” he said.  Mr. Williams said it gave him the feeling of doing something for the first time. “You know like you’re a little kid, and you done something good for the first time, and it gave you a rush and you felt good,” he said.  The overdoses have come on the heels of what had seemed like a series of accomplishments in the fight against the drug after public officials had warned of a public health crisis last summer.  In September, federal and city authorities conducted a sweeping crackdown, raiding 90 bodegas and charging 10 people related to the sales of K2. In May, city officials, including Mayor Bill de Blasio; the City Council speaker, Melissa Mark-Viverito; and Dr. Mary T. Bassett, the health commissioner, spoke of an 85 percent reduction in K2-related emergency room visits, citing the work of law enforcement and other city agencies.  But the overdoses this week were a sign that the potent drug, which experts say is made more appealing by prices as low as a $1 a cigarette, was still a force.  “We took a lot of the product off the streets and out of the warehouses, and for a while it was tougher to get it on the street,” said James J. Hunt, the special agent in charge of the Drug Enforcement Administration’s New York division. “But it’s back.”  Agent Hunt said most K2 originated in China, where the chemicals that give the drug its potency are produced. After being shipped here, the chemicals are sprayed on an inert plant before it is packaged and sold. “The whole guise here is to make people think it’s similar to marijuana,” he said.  He said that though the drug was outlawed in New York State in 2012, stores selling it sometimes tried to exploit a legal loophole, saying on packages that the substance was not for human consumption.  Agent Hunt said the large number of overdoses on Tuesday was probably the result of a “bad batch.”  “This stuff is mixed by bathtub chemists,” he said. “That’s why you see what happened yesterday.”  Hospital officials spoke about the stark human toll that the drug had taken on those admitted on Tuesday. Dr. Robert Chin, the chief of the emergency department at the Woodhull Medical and Mental Health Center, which treated the group of 33 people, said the patients were brought in by emergency medical workers in waves; he said the patients were extremely lethargic and disoriented.  “I could describe it as a deep sleep,” Dr. Chin said.  One man was so disoriented that he could not explain to a doctor who he was.  A spokeswoman for the hospital said it had received two more people with suspected K2 overdoses on Wednesday.  Though the police raids came up empty for the drug, residents continued to point at the local convenience stores.  “All these people that come around here don’t live around here,” said Alex Almanzar, 40, a resident living on the Bedford-Stuyvesant side of the subway station. “They gravitate here because of the K2. It’s the stores selling it that made it a problem area.”  Mr. Williams attributed the overdoses to the potent combinations of various drugs it can be mixed with and the hopelessness felt by many in the area.  "It’s like stress-related,” he said, adding that they have “no life no job, no family or friends.”  A version of this article appears in print on July 14, 2016, on page A23 of the New York edition with the headline: Police Raid Five Bodegas Amid Fears That Use of a Potent Drug Is Rising. Order Reprints| Today's Paper|Subscribe
No K2, also known as synthetic marijuana, was found in the raids, which came a day after 33 people were sent to the hospital for suspected overdoses.