KANSAS CITY, Mo. (AP) — Kansas City and a national gun safety advocacy group filed a lawsuit Tuesday alleging that several businesses and individuals trafficked firearms in the region while willfully ignoring evidence that the guns were being sold illegally.

The city was joined in the lawsuit by Everytown for Gun Safety Support Fund, a national gun safety advocacy group, which said it is the first such lawsuit filed against the gun industry in more than 10 years. The lawsuit alleges that the gun trafficking created a public nuisance in Kansas City, which has one of the highest homicide rates i...