In their delightful book of aerial photographs of Mesoamerican ruins, William Ferguson & Arthur Rohn write: "Raymond E. Merwin and Clarence L. Hay discovered Río Bec B in 1912. After the 1912 expedition, Río Bec B literally disappeared. During the 1930s several attempts were made by the Carnegie Institution of Washington to relocate it. New ruins associated with the site were discovered, but Río Bec B could not be found. It was finally rediscovered in May 1973 by a documentary film team from Princeton led by Hugh and Suzanne Johnston and accompanied by Gillett Griffin and Andrea Seuffert.
The site was quite difficult for us to find from the air. We located it by flying to the spot indicated on the map and then initiating a square search of the kind used by John Q. Royce when he was an aircraft carrier squadron commander in the Pacific during World War II. It took us about 20 minutes flying time to find the beautiful little temple nestled in a small clearing in the forest."
William M. Ferguson and Arthur H. Rohn with photographs by John Q. Royce and William Ferguson "Mesoamerica's Ancient Cities", p169-70.