Multiple states, including Colorado, are scrutinizing the Chinese app WeChat, as attorneys general are demanding information on how the app is following U.S. laws to prevent money laundering that is said to help fentanyl traffickers.

In a bipartisan effort with five other states, their attorneys general sent a letter to WeChat, a platform that has an estimated 19 million users in the United States and a billion in China.

Attorney General Phil Weiser and the other state officials expressed worries that the app’s integrated payment features have helped to grow the fentanyl crisis in the U.S.

“A growing body of well-documented evidence shows that WeChat is a central conduit for transnational money laundering operations, particularly those linked to the fentanyl trade,” the May 12 letter states. “These operations have exacerbated a crisis that is devastating American communities, including in the undersigned states, by enabling drug traffickers to launder drug proceeds with minimal detection.”

The letter to WeChat was also signed by the attorneys general of Colorado, North Carolina, South Carolina, Mississippi, New Hampshire, and New Jersey.

The attorneys general demanded that WeChat provide information to show that the app complies with state laws.

Setting a deadline, they asked WeChat to respond by June 11. The attorneys general asked the company to describe steps, if any, taken in response to public reports, indictments, intelligence assessments and other similar evidence of WeChat “being used to facilitate money laundering by fentanyl traffickers, including relevant terms of service, community guidelines and other policies and procedures.”

In announcing the demands on Monday, Weiser said in a statement, “The concerns that we raise here about WeChat are even more serious, enabling of money laundering and organized criminal organizations to prosper. WeChat needs to provide answers and respond in a meaningful fashion.”

According to a study from the Common Sense Institute, the overdose deaths cost Colorado $16 billion in 2023. The DEA’s Rocky Mountain Field Division seized a record 425.6 kilograms of fentanyl in 2023. Two milligrams of the synthetic opioid is considered a lethal dose.

In 2023, there were over 1,200 drug overdose deaths related to fentanyl. According to the Common Sense institute, that translates to an average of three deaths per day— more than all homicides in Colorado between 2021 and 2023.