From the GJ report:
Joseph V. Paterno testified to receiving the graduate assistants report at his home on a Saturday morning. Paterno testified that the graduate assistant was very upset. Paterno called Tim Curley, Penn State Athletic Director and Paternos immediate superior to his home the very next day, a Sunday, and reported to him that the graduate assistant had seen Jerry Sandusky in the Lasch Building showers fondling or doing something of a sexual nature to a young boy.
That is pretty specific.
Certainly specific enough for most normal people to be alarmed and then notify proper authorities.
How they still could stand the sight of Sandusky and be anywhere near him after hearing even an inclination of something like that, I’ll never understand.