In 1875, the Dallas Herald published an article by a former Fort Worth lawyer, Robert E. Cowart, who wrote that the decimation of Fort Worth's population, caused by the economic disaster and hard winter of 1873, had dealt a severe blow to the cattle industry. He further stated that the harm to the cattle industry, combined with the railroad stopping the laying of track 30 miles (48 km) outside of Fort Worth, had caused Fort Worth to become such a drowsy place that he saw a panther asleep in the street by the courthouse. Although an intended insult, the name Panther City was enthusiastically embraced when in 1876 Fort Worth recovered economically. Many businesses and organizations continue to use Panther in their name. The Fort Worth police have a panther prominently set at the top of their badge.
So I google searched the guy who wrote that article and this is what came up.
James M. Thurmond was born February 22, 1836 in Davis County, Kentucky to Philip Thurmond and Rebecca Ann Snead. He married Amanda J. Bentley on February 14, 1880 in Dallas, Texas. They had one son, James M. Thurmond, Jr.
He moved to Texas before 1870 and was appointed mayor of Bryan, Texas by Governor E. J. Davis in 1871. In 1876 Dallas mayoral terms were change from two-year to one-year terms and gave the city council the power to remove a mayor from office. J. M. Thurmond was elected Mayor of Dallas in April, 1879 and re-elected in April, 1880. In September 1880 the city council voted to remove him and elected J. J. Good to fill the vacancy.
On March 14, 1882, Judge J. M. Thurmond was shot and killed in the courtroom by Robert E. Cowart as the result of an argument between the two men stemming from the removal of Thurmond as mayor. He was interred at Greenwood Cemetery, Dallas, Texas.