U.S. Immigration and Customs Enforcement has for years provided inadequate medical care at its detention facilities, leading to in-custody deaths, according to a report by a coalition of advocacy groups.

The American Civil Liberties Union, Detention Watch Network and National Immigrant Justice Center examined reports filed by an ICE review board in charge of investigating detention deaths. The coalition examined reports from 2010 to 2012, but advocates say the problem is ongoing and getting worse, especially in Arizona, where a detention center 65 miles south of Phoenix is known as the deadliest in the country.