Artist N.C. Wyeth's painting "The Encounter on Freshwater Cliff" is shown in this undated FBI Reward handout poster released on August 18, 2015.The FBI is offering a $20,000 reward for tips leading to the recovery of two paintings by N.C. Wyeth stolen from a Maine collector two years ago in what officials on Tuesday called the most significant art theft in that state's history. REUTERS/FBI/Handout via REUTERS FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS