The North Carolina woman, Elizabeth "Liz" Waddell, disappeared after going for a swim at Grand Anse Beach, according to her family.
Officials continued investigating a home in Olney on Monday, with federal agents on scene and an expanded perimeter remaining in place.
Eugene Horsch, 44, was indicted on federal charges Thursday for allegedly having fake DEA credentials, according to officials.
Amanda Stofer, McHale's daughter, said news of the search initially gave her hope that investigators had found answers about her mother's disappearance.