Toensing, the St. Paul Pioneer and Democrat, January 7, 1862; and the Minnesota Legislative Manuals, 1863, 1864, and 1866 list his last name as Thacher. The Minnesota Legislative Manuals, 1862 and 1879 list both Thacher and Thatcher. The Minnesota Legislative Manual, 1889 lists Thatcher.
He came to Minnesota in 1856 and settled in Zumbrota.
The St. Paul newspaper traditionally listed members who won the election with party affiliation (Democrat or Republican). In 1862 they only identified the Democrats, the assumption is that the rest were Republicans. Since he wasn't identified as a Democrat, the assumption is that he was a Republican. (St. Paul Pioneer and Democrat, January 7, 1862)
He died in Zumbrota, Minnesota.