Police swarmed a Connecticut park near Yale University and searched people’s homes for drugs Thursday in an effort to prevent more overdoses from a batch of artificial “marijuana” blamed for hospitalizing more than 70 people.

Social workers and mental health professionals also responded to the New Haven Green, where most of the overdoses happened Wednesday. Authorities described a chaotic scene where people were dropping to the ground unconscious, others vomiting and some becoming lethargic.

Officials said 76 people overdosed Wednesday and six more were treated Thursday. Officials weren’t certain whether Thursday’s cases involved the same batch of “K2” synthetic marijuana. No deaths were reported, and most of those brought to local hospitals have been discharged.

Synthetic marijuana, called “spice” and other names, usually is ordinary dried plant material sprayed with chemicals or other substances. It has been blamed for overdoses across the country. Some of the New Haven victims tested positive for the powerful opioid fentanyl, also blamed for overdoses, but authorities believe this week’s overdoses were caused solely by synthetic marijuana.

Police Chief Anthony Campbell said one of three people arrested in connection with the overdoses apparently gave K2 away for free in an effort to get people hooked. The names of the suspects haven’t been released.

Campbell said New Haven provides an array of services to people addicted to drugs, many of whom come from other towns where such treatment programs aren’t available.

“New Haven is a place where we really are trying to help people,” Campbell said. “Someone … with malice in their heart took advantage of that, took advantage of this vulnerable population. But that will not stop this city from reaching its hand out to those who are in need and treating them and providing those services.”

The 16-acre Green, which the National Park Service says dates back to 1638 and is one of the oldest in New England, is a focal point of downtown New Haven. It’s surrounded by parts of Yale University, shops, churches and government buildings, and serves as a hub for area bus service.

Campbell also said officers were executing search warrants Thursday in an effort to get all the bad drugs off the streets. He said that in addition to state charges, the suspects could also face federal charges.

Mayor Toni Harp said plans were being finalized for Jim Carroll, President Trump’s nominee for drug czar, to visit New Haven on Monday.

“This is happening nationwide,” Harp said. “We’re eager to raise awareness at the highest levels of the federal government for a better sense of what happened and the challenges that urban centers face in terms of combatting a persistent, vexing presence of people with substance abuse disorder.”

Officials were still trying to determine what exactly made people sick. Toxicology tests remained pending. Doctors said some victims improved after being given the opioid overdose antidote drug naxolone, while others did not.

Gov. Dannel P. Malloy said the state departments of Public Health and Mental Health and Addiction Services were helping New Haven officials. He said state health officials delivered 50 doses of naxolone to the city to help replenish its supply.

“Today’s emergency is deeply troubling and illustrative of the very real and serious threat that illicit street drugs pose to health of individuals,” the Democratic governor said.

New Haven first responders were called to a similar overdose outbreak on the Green on July 4, when more than a dozen people became sick from synthetic marijuana. The city also saw more than a dozen synthetic marijuana overdoses in late January. No deaths were reported in either outbreak.

The state Senate Republican leader, Len Fasano, of North Haven, criticized New Haven officials on Thursday for not addressing drug use on the Green — a claim the mayor disputed. Fasano said the Green has become “a place of despair” and “no longer an attraction for families or economic development.”