Officials continued investigating a home in Olney on Monday, with federal agents on scene and an expanded perimeter remaining in place.
Forensic evidence recovered from the electronic devices of Lynette Hooker's husband, Brian Hooker, have led investigators to new areas of interest.
The U.S. Coast Guard has seized the boat used by Americans Brian and Lynette Hooker.
Authorities in California said Saturday they didn't find the remains of Kristin Smart, a 19-year-old college student who went missing in 1996, after finishing their search of a home tied to the man convicted of killing her.
Nearly 30 years after 19-year-old Kristin Smart disappeared, California investigators conducted new search warrants as part of their ongoing probe into the location of her body.
The U.S. Coast Guard Southeast Division said Tuesday it is "asking the public for info about the disappearance of Lynette Hooker."