Republicans on the House Oversight Committee have launched an investigation into a controversial DEA strategy that allowed large fentanyl shipments to reach the streets. The committee's chairman, Rep. James Comer, sent a letter Monday to Attorney General Todd Blanche requesting records related to this tactic. Concerns have been raised in New Mexico, where whistleblowers reported being ordered not to seize fentanyl pills. Last week, the state’s attorney general sued the U.S. Justice Department for similar records. The DEA's strategy, known as allowing drugs to “walk,” has been criticized for contributing to the fentanyl crisis.