Evanston Police Detectives and Investigators from NORTAF identified a 26- year old Evanston man as a prime suspect in the Dec. 21 stabbing death of David L. Branch at 2120 Seward, said Commander Tom Guenther, public information officer of the Evanston Police Department.  The man was charged with two counts of first degree murder, said the Commander. On Dec. 23, a magistrate set bond at $2 million.