Associated Press: A mystery is unfolding in the world of college fundraising: During the past few weeks, at least nine universities have received gifts totaling more than $45 million, and the schools had to promise not to try to find out the giver's identity.

One school went so far as to check with the IRS and the Department of Homeland Security just to make sure a $1.5 million gift didn't come from illegal sources.

"In my last 28 years in fundraising ... this is the first time I've dealt with a gift that the institution didn't know who the donor is," said Phillip D. Adams, vice president for university advancement at Norfolk State University, which received $3.5 million.

The gifts ranged from $8 million at Purdue to $1.5 million donated to the University of North Carolina at Asheville. The University of Iowa received $7 million; the University of Southern Mississippi, the University of North Carolina at Greensboro and the University of Maryland University College got $6 million each; the University of Colorado at Colorado Springs was given $5.5 million; and Penn State-Harrisburg received $3 million.

It's not clear whether the gifts came from an individual, an organization or a group of people with similar interests. In every case, the donor or donors dealt with the universities through lawyers or other middlemen. Some of the money came in cashier's checks, while other schools received checks from a law firm or another representative.

Read more hot stories Moms Are Talking About.