The source, who spoke on a condition of anonymity, said Pahlavi's body was discovered in his South End apartment at 2:11 a.m.
Pahlavi, the second son of the late shah, attended Mount Greylock Regional High School in Williamstown and Harvard University, his Web site said.
"Like millions of young Iranians, he too was deeply disturbed by all the ills fallen upon his beloved homeland, as well as carrying the burden of losing a father and a sister in his young life," Pahlavi's brother, Crown Prince Reza Pahlavi, said in a statement.
Members of the shah's family moved into exile after the 1979 Islamic revolution, and many of them live in the United States.
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