Branden Mattier, of the South End, allegedly told the charity organization his aunt, Onevia Bradley, was expected to have a double amputation in the future after she was injured in the Boston Marathon bombings, WFXT-TV, Boston, reported Tuesday.
He submitted a letter allegedly from the chief of trauma services at Boston Medical Center to provide proof of his aunt's injuries.
The One Fund Boston -- which hands out donation money to the Boston Marathon bombing victims -- became suspicious of Mattier's claim and handed it over to the attorney general's office to investigate, WFXT reported.
The hospital said they never treated anyone with Bradley's name for bombing injuries and denied providing the letter.
Investigators also confirmed that Mattier's aunt had been dead for 10 years.
State police arrested Mattier when he accepted a simulated check for $2.195 million delivered by an undercover state trooper, WFXT reported.
He was charged with attempted larceny over $250 and identity theft.