Police released images of the suspects Sunday. Detective Robert Costigan called it a "particularly harrowing crime" that has had a devastating impact on the 83-year-old victim.
Police said a man posing as a plumber convinced the woman to let him into her home in the southeastern London borough of Greenwich, saying there was a leak.
When the man left, the woman realized that items had been stolen, including a heart-shaped locket and a heart-shaped box that both contained her husband's ashes.
Police believe a second man entered the home while the victim was distracted by the man pretending to be a plumber.
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