A sandwich restaurant chain says it's looking into how a dead frog got into a customer's salad in Manhattan Monday. The customer found the small frog in her salad from a Pret A Manger store on 47th Street and Sixth Avenue, according to her colleague Kathryn Lurie, who photographed it and posted it to the photo-sharing app Instagram. Lurie, an editor at The Wall Street Journal, said on Twitter her co-worker wanted to remain anonymous but that "she was pretty shaken, understandably." It's not clear how the frog got into the salad. Pret said in a statement: "Our lettuce is...