In each case, the college hears from a lawyer, banker or other middleman. There's a large check or checks from a law firm. And instructions: The money should go for scholarships and the school should make no effort to track down the donor.
It's a mystery worthy of Sherlock Holmes or the cast of "CSI." An anonymous donor has so far given $76 million to 15 different colleges and universities and nobody -- at least publicly -- knows who's responsible.
The fund-raising world has been abuzz for weeks speculating on who the donor or donors might be. So far, there have been lots of clues, denials and no shortage of theories. But the source of the money has yet to surface.
Hunter College in New York City got $4 million for scholarships and $1 million to be used at president Jennifer Raab's discretion.
"We were very excited but we had to wonder if some things are too good to be true," Raab recalled of the two letters that arrived to her development office from a bank on behalf of the donor.
A quick call to the bank and the school confirmed the gift as a legitimate one but did not yield any clues about the donor's identity.
(Raab did ask the bank, located somewhere "in the western part of the country," to forward a thank you note to the donor.)
"It's an incredibly transformative gift for us," she said of the school that's one of the City University of New York's 20 colleges. "This is certainly the largest scholarship gift we've ever received."
Indeed, for most of the schools, this was the largest gift in their history.
Hunter serves an economically disadvantaged population. It has a significant population of black, Hispanic and southeast Asian students. Many are the first in their families to go to college. About 65 percent are women.
With an annual tuition of $4,600, the $4 million gift will go a long way.
"Hunter College is a place where the American dream can come true," Rabb said.
The 15 schools to receive the money to date are:
Michigan State University: $10 million
Purdue University: $8 million
University of Iowa: $7 million.
The University of Alaska-Anchorage: $7 million
Binghamton University: $6 million
University of Southern Mississippi: $6 million
The University of Maryland's University College: $6 million
The University of Colorado at Colorado Springs: $5.5 million
Hunter College: $5 million
Montclair State University: $5 million
Norfolk State University: $3.5 million
Pennsylvania State University-Harrisburg: $3 million
The University of North Carolina-Greensboro: $1.5 million.
University of North Carolina at Asheville: $1.5 million
Kalamazoo College: $1 million
Don't expect any more details about the donor from Hunter's Rabb or any of the other colleges. Even if they know more, they aren't sharing.
For instance, Purdue University refused to discuss the specifics about how the money was received to keep "with the spirit of the donor's wishes."
"We can best honor the donor by respecting his or her wishes and not speculating or discussing the details," spokeswoman Jeanne Norberg said.
So ABC News reached out to the experts, those who raise money for a living -- and even those who try to profile serial killers -- to find out how they would go about trying to solve this mystery.