Several jurisdictions in Colorado, including Castle Rock, Aurora, and Parker, are pursuing legal action against Denver over its sanctuary city policies, which they argue have led to an influx of illegal migrants and subsequent crime, particularly from the Venezuelan gang Tren de Aragua. Castle Rock's town council voted unanimously to explore suing Denver, citing the negative impact of welcoming over 42,000 immigrants since December 2022. Local leaders express frustration, claiming these sanctuary policies do not protect citizens but rather shield criminals. Additionally, Douglas County and El Paso County are involved in a separate lawsuit against the state to challenge laws that restrict local law enforcement's cooperation with federal immigration authorities. The suburban officials emphasize that their goal is not to deport immigrants but to prevent further influxes that they believe Denver cannot manage effectively. Concerns over crime, including gang activity and threats to local residents, are driving these municipalities to take action.