Two men suffered apparent overdoses of a club drug at a Boston concert Saturday night while the same night in New York City, a University of New Hampshire student died at a music festival after apparently taking the drug, which is also suspected in a death Tuesday at Boston’s House of Blues.
New York City officials said the deaths of UNH student Olivia Rotondo, 20, of North Providence, R.I., and a man from Rochester, N.Y., who attended the Electric Zoo Music Festival appeared to be connected to the club drug MDMA, a pure form of ecstasy commonly called by the street name Molly.
Also, in Brockton Saturday night, police arrested two men on charges of dealing the drug.
In the South Boston Seaport area, ambulances transported three men separately away from a performance by the band Sound Tribe Sector 9 at the Bank of America Pavilion over a period of about 2½ hours, said Boston EMS spokesman Nick Martin.
Two appeared to have overdosed on MDMA or another ecstasy-type drug, and another appeared to have taken a hallucinogen, State Police spokesman David Procopio said.
One man’s condition was critical and the other two were in serious condition, said Officer Neva Coakley, a Boston police spokeswoman.
No Boston police were inside the pavilion Saturday night, and they learned of the apparent overdoses when they were alerted by State Police.
Boston police spokeswoman Cheryl Fiandaca said the department had put extra resources into city neighborhoods to help quell violence and that the pavilion is a venue where violence or overdoses are unusual.
“It is not uncommon for details to go unfilled when staffing is increased in other areas,” Fiandaca said in an e-mail Sunday.
She also said police presence has been stepped up in the city’s nightclubs in the wake of three apparent overdoses, one fatal, at the House of Blues on Tuesday. The drug-control unit made two arrests Saturday night and in the past week seized a large amount of ecstasy, said Fiandaca, who provided no further details.
Representatives for Live Nation, owner of the pavilion and the House of Blues, did not respond Sunday to requests for comment.
In Brockton Saturday night, local and State Police arrested three men from Maine on outstanding felony warrants and for possession of what appeared to be about 16 grams of MDMA and 12 grams of heroin.
Patrick Lee, 32, of Bangor, and Mark White, 25, of Argyle, were charged with narcotics possession and conspiracy to violate drug laws, while Brandon Kerr, 23, of Bangor, was arrested on felony warrants, according to a statement from State Police. All are scheduled to be arraigned in Brockton District Court on Tuesday.
New York City officials said that in addition to the deaths of Rotondo and Jeffrey Russ, 23, of Rochester, N.Y., at the electronic music festival, at least four other attendees became critically ill and were hospitalized.
The deaths caused the cancellation of Sunday’s festival events.
Rotondo fell ill at about 8:45 p.m. Saturday and was taken from the festival by ambulance to Manhattan’s Metropolitan Hospital Center, where she was pronounced dead about 45 minutes later, said Officer Sophia Tassy, a spokeswoman for the New York Police Department.
Police received a call from Harlem Hospital at about 3:20 a.m. Sunday, Tassy said, reporting that Russ had been brought to the emergency room from the festival. Russ was unresponsive upon arrival and was transported to the intensive care unit, Tassy said, where he was pronounced dead.
Rotondo, a junior at UNH, was a member of the school’s dance team.
Danielle DeFranzo, a senior captain on the UNH Dance Team, said she and Rotondo met through the team about two years ago and became close friends.
“She was the type of person that got along with everyone and could talk to anyone,” DeFranzo said by e-mail. “She always had a smile on her face and was always cracking jokes.
“She always brightened up my day with her smile, laugh, and fun-loving attitude, which I will miss the most,” DeFranzo added.
Katie Laurent, a fellow dance team member, said Rotondo’s death was devastating.
“This whole thing is just a complete shock to everyone, and I hope I wake up tomorrow and that this will all be a dream,” Laurent said by e-mail. “I will always remember her as the girl who didn’t care what people thought, and she taught me to always live in the moment and cherish everything you have.”
University officials on Sunday released a statement expressing sadness.
“We extend our deepest sympathies to her family and friends during this difficult time, and are focused on providing support and resources to our campus community,” spokeswoman Erika Mantz said in the statement.
A North Providence neighbor, who declined to give her name, said she had known Rotondo, her older sister, and parents for about the past 16 years.
“Just watching them grow up . . . the Halloweens, watching them on the trampoline just being kids and being beautiful children,” the woman said by phone. Her voice trembled with emotion at times. “These things shouldn’t happen, not at 20 years old.”
Rotondo graduated from Mount Saint Charles Academy, a Catholic junior-senior high school in Woonsocket, R.I., according to the neighbor and friends, some of whom expressed their grief on social media Sunday.
Despite the deaths, Sam Miller, a spokesman for the New York City Department of Health and Mental Hygiene, said in an e-mail that the city has not seen any notable rise in the prevalence of MDMA.
He said the department estimates there are fewer than 10 ecstasy overdoses a year in New York City.
The weekend’s overdoses came just days after the death early Wednesday morning of 19-year-old Brittany Flannigan, a native of Derry, N.H., who was about to begin her sophomore year at Plymouth State University.
Flannigan was one of three young people rushed to Beth Israel Deaconness Medical Center after the conclusion of a Tuesday night show by Zedd, an electronic music producer and disc jockey, at Boston’s House of Blues. A man in his 20s and a 24-year-old woman were listed in serious condition Wednesday.
Shortly after those overdoses, Boston officials warned that the low-cost drug is seeping into the club and college social scenes. Boston University police have posted information about MDMA on their website, providing definitions and warnings about the dangers of the drug.
The recent spate of deaths and overdoses holds echoes of the two deaths and 20 hospitalizations that accompanied a July 2012 electronic music festival at the Comcast Center in Mansfield, where the local police chief said the use of alcohol, ecstasy, PCP, LSD, and marijuana was pervasive.
A funeral Mass for Flannigan will be said Wednesday at 10:30 a.m. in St. Anne Church in Hampstead, N.H., with visiting hours Tuesday in Brookside Chapel & Funeral Home in Plaistow, N.H., according to the funeral home’s website.
Globe correspondent Zachary T. Sampson contributed to this report. Jeremy C. Fox can be reached at email@example.com. Follow him on Twitter @jeremycfox. Matt Rocheleau can be reached at matthew.rocheleau
@globe.com. Follow him on Twitter @mrochele.