It is common in cases of child molestation that victims do not report their abuse until other similar allegations surface.
The facts alleged by these new victims appear to be similar to those alleged by the first eight victims. The victims were all young boys who met Sandusky through his charity, The Second Mile. Sandusky gave the boys gifts and took them to football games. He began physically touching the boys, which eventually became sexual assaults.
These kinds of similiarities tend to reinforce the truth of each of the allegations. If specific enough, they can be classified as the defendant's modus operandi, or M.O.