Some six weeks before her husband joined the church in 1882, 12-year-old Julius immigrated to Utah under the care of returning Mormon missionary Ulrich Stauffer (1838–1905).
[3] Billeter and Marie Emilie Wilker (1873–1951) were married on June 24, 1891, in the Logan Utah temple of the Church of Jesus Christ of Latter-day Saints.
Less than four weeks after the birth of his first daughter in 1892, Billeter returned to Switzerland and proselyted for two years as a missionary in the Swiss-German Mission of the LDS Church.
Marie and their infant daughter moved to Paris, Bear Lake County, Idaho, where she lived with her widowed mother, Maria Emilie Wilker (née Kuenzlin; 1842–1930).
In the spring of 1894, Billeter started doing intensive genealogical research in order to take the many lists of names with him upon his return to the United States.
[4] When Billeter returned to Utah in July 1894, the Salt Lake Temple – built in neo-Gothic style according to plans of church architect Truman Osborn Angell (1810–1887) and dedicated in April 1893 – was in full operations.
Professor Richard Theodor Haag (1867–1947) of the Latter-day Saints' College in Salt Lake City and a native of Stuttgart, Germany, supported Billeter's recommendation.
On January 24, 1896, the "Salt Lake Beobachter", a weekly, German-language newspaper published in Salt Lake City at that time, reported: "According to the carefully developed plans of these brethren supported by the Authorities – a qualified representative will leave in the near future for Germany and Switzerland to help those who are sufficiently interested to make a prepayment of Five Dollars for each record."
Various place names are mentioned in his letters: Lauterbrunnen, Zweiluetschinen, Luetschental, Burglauenen, Grindelwald, Interlaken and Unterseen, as well as Zweisimmen and Erlenbach im Simmental, along with Rueegsau, Huttwil, Kallnach, Bruettelen, Erlach, Biel, etc.
During Billeter's absence, Haag had accepted a position at the "Weber Stake Academy" in Ogden, Utah, and therefore moved away from the Mormon capital.
In order to better coordinate his work with Haag, Billeter moved his family to Ogden, where Emilie opened a dressmaking shop on the city's main street.
Immediately prior to being released as a Mormon missionary, Ezra Louie Kunz (1887-1985) noted the following in his diary on 7 June 1909: "I spent the day mostely at Billeters talking over genealogy.
With church assistance, the six members of the Billeter family were able to become passengers on one of the first ships to sail from France after the Armistice of Compiègne was signed on November 11, 1918, and return to their home in Utah.
[12] Not long thereafter, the descendants of numerous earlier Mormon immigrants from Switzerland realized that as a result of Billeter's return they were no longer enabled to obtain genealogy records.
Despite the sympathetic obituary written by Robert Oehler – the former Latin teacher and as of 1932 a staff member at the Swiss National Library, who was responsible for the two volume, first edition of "Familiennamenbuch der Schweiz" ["Swiss Family Surname Book"] – the results of Julius Billeter's genealogical research are to be used very cautiously with constructive criticism.