The source speculated that someone put up a substantial down payment for the 2.2 kilograms found Friday. The cocaine was in hollowed-out books in a package in the mailroom of the Romance Languages Department at Penn.
"Somebody had to lay out some real heavy money," the source said. "They don't give stuff like that on consignment."
Police said the cocaine would have cost about $55,000 wholesale and was worth $1.1 million on the street.
The package of books had been in the mailroom in Williams Hall for about three weeks, police said. It was found by a teaching assistant, and police had been watching it, hoping to catch someone picking it up.
However, rumors about the cocaine find spread around campus and the Daily Pennsylvanian, the student newspaper, broke the story Tuesday.
The address on the package contained the name of a person, the Romance Language Department, and the address of the Pi Lambda Phi fraternity house on Spruce Street near 39th. The fraternity has denied any knowledge of the package.
The box, postmarked from Colombia and Miami, carried the return address of a Colombian book dealer, police said.
There was a similar incident about two years ago in which cocaine was found in hollowed-out books sent to another Penn frat house. No details on that incident have been available.
The police source said the address on the latest package had been "left vague enough so you could not attribute it to one person."
Robert LaRatta, assistant agent in charge of Philadelphia's U.S. Customs office, said that about 26 million pieces of mail came into the United States in 1986, and customs focuses on items it feels are suspicious-looking.
Robert Browne, president of Pi Lambda Phi, said police had not interviewed anyone there. Asked if the frat had had any problems with cocaine, he replied: ''Absolutely not."
Dr. Roger Soloway, chairman of the Faculty Senate, commented, "I would offer the suggestion that the university is simply part of society and that, I guess, I'm not surprised that its name would be associated in some way with people trying to bring drugs into this country . . . I really think there is no conclusion one can derive from the fact (that cocaine was discovered on campus)."