Escucha Mi Voz Iowa, an immigrant-led advocacy group, is calling for more transparency after the U.S. Marshals Service, only 12 out of the 61 people detained were accused of being "violent criminals." The Iowa City enforcement involved armed U.S. marshals carrying out an operation at a busy intersection on July 23. David Goodner, Escucha Mi Voz executive director, said he reached out to Deputy U.S. Marshals Service.