PHOENIX (AP) — Arizona’s chief attorney has issued a cease-and-desist letter to a company touted by a church where President Donald Trump held a rally that claims its air filtration system neutralizes the coronavirus.

Attorney General Mark Brnovich also sent a warning letter to Dream City Church. Leaders of the church posted a widely circulated video claiming the technology they used “kills 99 percent of COVID within 10 minutes.”

The company that provides the products is Clean Air EXP. Brnovich said it has continued to advertise that its products neutralize 99.9% of viruses that are “COVID-19 surrogates.”

Covid-19 refers to the disease caused by the coronavirus. Brnovich said the company tested a virus that causes the common cold, not the coronavirus, which has killed over 1,500 people in Arizona.

Dream City Church was placed on notice that misrepresentations and false promises related to the safety of church facilities may violate the Arizona Consumer Fraud Act.

In a statement posted on its website, Clean Air EXP said there is recent confusion around the claims made by one of its customers. It says it used a third-party certified lab on the “best coronavirus surrogates available” and found their patented technology leads to 99.99% of elimination. “We do not, however, eliminate COVID-19 at this time,” it said.

Dream City Church also issued a statement saying its leaders should not have used the word “Covid” and “coronavirus” interchangeably.

“We hope to alleviate any confusion we may have caused,” it said.

The claims came as cases in Arizona surge, making it one of the states with the highest infection rates.