According to the search results, there are different ways to measure the murder capital of the US. Here are some of the findings:

• St. Louis, Missouri had the highest murder rate for any major American city in 2019, with 64.54 murders per 100,000 residents.
• St. Louis, Missouri also has the highest murder rate of any US city of 69.4 murders per 100,000 people in 2023.
• Jackson, Mississippi had the highest homicide rate among major US cities for the second straight year in 2022.
• New Orleans, Louisiana had the highest murder rate per capita in the US in 2022, with 74.3 homicides per 100,000 people.
• The District of Columbia has the highest murder rate in America, at 49.2 murders per 100,000 people.
• Chicago, Illinois had the highest number of homicides in the United States in 2022, with 697 total homicides.

Therefore, depending on the year and the criteria used, different cities can be considered the murder capital of the US.