"As a result of our public appeal for help, a courageous and compassionate individual came forward to provide the assistance needed to properly bury the deceased," Worcester police said in a statement.
Sgt. Kerry Hazelhurst said the body was no longer in Worcester and had been entombed, but he would not say where.
A day earlier, police in Worcester, about 50 miles west of Boston, pleaded for a resolution, saying they were spending tens of thousands of dollars to protect the funeral home where Tsarnaev's body had been kept since shortly after it was released by the medical examiner on May 1. He was killed in a getaway attempt after a gunbattle with police.
Massachusetts Gov. Deval Patrick said Thursday that he's glad the Tsarnaev family found a burial location but does not know where it is.
He called the weeklong drama over where to bury Tsarnaev a circus and said he hopes attention can now return to caring for the victims of the bombing, which killed three people and injured 260.
Tsarnaev's body had been at the Graham Putnam & Mahoney Funeral Parlors, where director Peter Stefan said he could not find a community willing to take the body.
That included Cambridge, where the family had lived for a decade, and what Stefan said were dozens of other communities where people had offered to donate burial plots. He declined to speak with reporters Thursday.
The body was in the custody of Tsarnaev's uncle, Ruslan Tsarni, who came from Montgomery Village, Md., to handle arrangements after Tsarnaev's widow, Katherine Russell, asked to have his body released to her in-laws.
In Russia, Tsarnaev's mother claimed authorities wouldn't allow her son's body into the country so she could bury him in her native Dagestan, but Russian officials would not comment on that contention.
An expert in U.S. burial law said the resistance to Tsarnaev's burial was unprecedented in a country that has always found a way to put to rest its notorious killers, from Lee Harvey Oswald to Adam Lanza, who gunned down 20 children and six educators at a Newtown, Conn., elementary school last year.
Tamerlan and Dzhokhar Tsarnaev, ethnic Chechen brothers from southern Russia and living in Massachusetts, are accused of planting two shrapnel-packed pressure-cooker bombs near the marathon finish line.
Dzhokhar, who was captured hiding in a tarp-covered boat outside a house in Watertown, a Boston suburb, was charged with using a weapon of mass destruction to kill. Their mother has said the charges against them are lies.
In Washington, the first in a series of hearings to review the government's initial response to the bombing began Thursday.
Boston Police Commissioner Edward Davis testified that FBI agents did not tell Boston police they had receiving warnings from Russia's government in 2011 about Tamerlan Tsarnaev and had performed a cursory investigation.
Davis said none of four people he had assigned to the FBI's Joint Terrorism Task Force was aware that the FBI investigated the vague warning, found nothing and closed the file.
Davis said he would have liked to have known but conceded that it might not have prevented the attack. The commissioner said his detectives would have wanted to interview Tsarnaev.
"The FBI did that and they closed the case out," he said. "I can't say I would've come to a different conclusion based on the information at the time."
The committee chairman, Rep. Michael McCaul, R-Texas, said the hearing will be the first in a series to review the government's initial response, ask what information authorities received about the brothers before the bombings and whether they handled it correctly.
Associated Press writers Mark Pratt and Steve LeBlanc in Boston and Alicia A. Caldwell in Washington contributed to this report.