First instance judges ordered the suspension of the instant messaging service WhatsApp in four different cases in Brazil, leading to an effective block in three cases. The suspensions (blocking orders directed at ISPs) were determined to force the company to cooperate with law enforcement authorities by handling data about the individuals being criminally investigated.
The circumstances of all the cases are not entirely clear, since some of the decisions and procedures were not public in order to protect the investigation efforts. In the two most recent cases - one in April 2016 (issued in the State of Sergipe) and the other in July 2016 (issue in the State of Rio de Janeiro) -, however, the decisions were eventually made public, exposing that authorities were seeking for a real-time interception of messages sent using WhatsApp. In both cases, the company did not handle the data and informed that the real time interception was impossible due to the use of end-to-end cryptography on the app.
After the April 2016 decision (issued by a judge in the City of Lagarto, State of Sergipe), two lawsuits have been brought before the Brazilian Supreme Court to address the constitutionality of the suspension.
The ADI 5527 (summary here), proposed by the political party named "Partido da República" (PR), claimed that the article 12, III and IV of the Civil Rights Framework for the Internet should be considered unconstitutional. The legal provisions allow the suspension of a service that fail to protect users' personal data and privacy.
The ADPF 403 (summary here) was proposed by the political party named "Partido Popular Socialista" (PPS), requesting the direct declaration of unconstitutionality of sections III and IV of art. 12 of the Brazilian Internet Civil Rights Framework in the light of the fundamental right to freedom of expression (article 5, IX of the Brazilian Constitution) and the lack of proportionality of the order. In the course of this procedure, Justice Ricardo Lewandowski issued an interim order to prevent the suspension of WhatsApp determined by the Rio de Janeiro's judge in July 2016.
Considering the technical issues involved in these two cases, the Supreme Court held a two day public hearing on encryption and the blocking of WhatsApp.
A timeline of all service blocks in Brazil and case materials is available here.