Dog shootings and mysterious letters initially put Berkowitz on Intervallo s radar.
On Christmas Eve 1976, Intervallo and Chamberlain were called to probe the shooting of a German Shepherd. By that point, Berkowitz had already shot six people in three separate incidents in the Bronx and Queens, killing one, Donna Lauria. She was 18.
Four months later, the Yonkers cops investigated the shooting of a black Labrador retriever hit by a .22 caliber bullet in the dog s backyard. The Labrador was owned by Sam Carr, the apparent Sam in Son of Sam. Both dog shootings occurred close to Berkowitz s home.
After searching the area, Intervallo and Chamberlain determined the only window that had a direct line to Carr s Warburton Avenue backyard was Berkowitz s apartment 7E.