The commander of a key Olympic security force has stepped down and contracts for some basic safety equipment have yet to be awarded, heightening concerns about Brazil’s preparedness just four months before the start of the 2016 Olympic Games in Rio. Col. Adilson Moreira resigned and this was confirmed by Brazil’s Justice Ministry.

Moreira headed one of several security forces involved in the games, the National Force for Public Security, which is sending about 10,000 police and other law enforcement staff to Rio. The Justice Ministry declined to disclose the reason for Moreira’s departure, but Brazilian media reported that Moreira stepped down after sending an e-mail to colleagues that was critical of the then President Dilma Rousseff. Moreira couldn’t be reached for comment. Moreira is the second high-profile official connected to the games to exit in recent days. Brazil’s Sports Minister, George Hilton, had resigned as part of a cabinet reshuffling linked to Rousseff’s growing political woes.