IN BODY PROBEPerson With Medical KnowledgeMay Be ThiefLA CROSSE, (/p)—Discovery of the body of Perry Brinstad, stolen from its grave in Campbell cemetery here on Sept. 20, providedauthorities today with evidence tending to confirm the belief that a medical practitioner or student was involved in the theft.Wrapped in canvas and tied with binder twine, the body was foundby~a tiihori ties-on-Petti bone-isiandin the Mississippi river. The island,used as a tourist camp and park, is opposite the cemetery and about a quarter, of a mile from the grave Marks on the body, authorities said, were similar to those left bv post mortenis. Search for someone interested in medical experiments was started.Brinstad, who was’70, died at ahospital and left no near relatives The theft of his body was dis* covered* wjieu . a cemetery care* taker noticed the grave had been disturbed. Police quietly conducted a search until .the body, was iound yesterday*