A Utah man who allegedly threatened to beat an informant in an artifact looting case with a baseball bat has been charged with retaliation, prosecutors say.

Prosecutors said Monday that Charles Denton Armstrong, 44, of Blanding, Utah, admitted threatening an unnamed antiquities dealer who served as a key informant in a wide-ranging case that saw the indictments of 24 people on charges of looting and selling Native American artifacts, the Los Angeles Times reported.

Officials said Armstrong's doctor, James Redd, also of Blanding, killed himself after being arrested in connection with the investigation and Armstrong had vowed revenge on the informant, allegedly telling a Bureau of Land Management agent he wanted to tie the informant to a tree and beat him with a baseball bat.

The Times said the arrests of the accused artifact looters has caused resentment among residents of the Four Corners region of Utah, who blame the probe for Redd's suicide. The newspaper said Utah's two Republican senators have complained to the Obama administration about the way the arrests were carried out.