Where did you see that?
Trump carried Uvalde County 59.7% to 39.4%.
Live election results: 2020 Texas results
Live 2020 Texas election results and maps by country and district. POLITICO's coverage of 2020 races for President, Senate, House, Governors and Key Ballot Measures.www.politico.com
You're correct. I was reading the absentee ballot voting totals, which Biden won by 32 percentage points. But, yes, the overall county vote went to Trump:
Donald J. Trump 56.90%
Joseph R. Biden 42.29%
However, the police chief is in fact a Democrat. Also, Uvalde County is largely Hispanic, FYI.