Maura Isles (Sasha Alexander) wears this yellow cashmere long sleeve shirt in the first episode of season 4 of Rizzoli and Isles.

It is the Banana Republic Silk Cashmere Crew-Neck Sweater in Yellow. Buy it HERE: https://bananarepublic.gap.com/browse/product.do?vid=1&pid=389993122&searchText=YELLOW+LONG+SLEEVE