Clem didn't give that information away until 77 or 78, this happened in 69. The police searched the Spahn area at various times through the years looking for Shea, Clem was looking for parole, and drew a map for the authorities.
I think they were looking for Shea. From the time of his disappearence, the police searched Spahn periodically trying to find Shorty. But hey, they could have been looking for weapons too. 8)