Mammadli was detained along with the center’s executive director, Bashir Suleymanli, and Elnur Mammadli, head of an allied group called International Cooperation of Volunteers. The other two were released, but Anar Mammadli was brought before a court and detained for three months.

According to APA news agency, the Prosecutor General’s Office accuses Mammadli of evading taxes of 20,000 manats (US$ 25,500) due on a grant of US$ 276,000, which the Washington-based National Democratic Institute gave EMDC to monitor the election. It also alleged that US$ 163,000 of this sum was transferred to Suleymanli’s private bank account. “The accusations, of tax evasion, illegal business activity, and abuse of power are invented,” Hafiz Hasanov, head of the NGO Law and Development, told reporters at a press conference.

Hasanov noted that since the government five years ago revoked the official registration of EMDC’s predecessor, the Election Monitoring Centre, Mammadli has conducted monitoring programs as a private individual. According to Hasanov, “EMDS did not have state registration, and Mammadli was forced to act as an individual taxpayer. But it is stupid to call this ‘illegal business activity’, because he had registration as a taxpayer ... Mammadli is under investigation because he monitored elections. The government does not want anyone independent of it to be involved in elections.”

EMDC’s reported the presidential elections “cannot be considered fair, free and transparent.” The statement was by the Organization for Security and Cooperation in Europe's (OSCE) report, which described the October 9 presidential election as “seriously flawed” and falling "well short of OSCE commitments in most areas.” According to official results, Aliyev won the poll with 85 percent of the vote.

The call from domestic human rights activists for Mammadli's immediate release was quickly picked up by international organizations. “Anar Mammadli has championed democratic and human rights for years in Azerbaijan, despite persistent pressure by the authorities to silence him and his colleagues,” said Denis Krivosheev, Europe and Central Asia Deputy Program Director at Amnesty International. “His arrest sends a chilling message to Azerbaijani civil society and adds to an atmosphere of self-censorship and fear that has grown under the authoritarian rule of Ilham Aliyev."

Meanwhile, Human Rights Watch (HRW), highlighted systemic human rights violations in Azerbaijan. In its December statement, HRW noted that in the run-up to and aftermath of the October presidential election, “the authorities engaged in an unprecedented crackdown to silence all voices of criticism and dissent.” The fundamental rights to freedom of expression, assembly and association have particularly been under attack.

According to HRW, Azerbaijan now has 143 political prisoners. These include journalists, bloggers, human rights defenders, civic and political activists, religious followers, and ordinary citizens, who have been “detained or imprisoned for political reasons, many in connection with exercising their fundamental freedoms.”

Mammadli was arrested a day before Western politicians, including EU Energy Commissioner Gunther Oettinger and British Foreign Secretary William Hague, attended the signing of a multibillion-dollar investment agreement, paving the way for the first gas deliveries from Azerbaijan to Europe.

International human rights organizations called on Hague to raise the issue of political arrests with the Azerbaijani authorities. Allan Hogarth, Amnesty UK's Head of Policy & Government Affairs, claimed that the Foreign Secretary "must honor" his own promise not to allow trade interests to trump human rights concerns in foreign relations and use the UK's key role in Azerbaijan's economic prosperity to make it clear that human rights abuses will not be tolerated. 

On December 17, the BP-led consortium developing the Shah Deniz field in the Caspian Sea announced the final investment decision (FID) for Stage 2. This decision is aimed to create a new Southern Gas Corridor to Europe. The total cost of Shah Deniz Stage 2 and the South Caucasus Pipeline (SCP) expansion projects will be around US$ 28 billion. 16 billion cubic meters per year of gas from Shah Deniz field will be carried some 3,500 kilometers to provide energy for millions of consumers in Georgia, Turkey, Greece, Bulgaria and Italy. The first gas is targeted for late 2018, with sales to Georgia and Turkey; the first deliveries to Europe will follow approximately a year later. President Aliyev said the agreements "will change the energy map of Europe."

After meeting with Aliyev, Hague told reporters in Baku that he had raised Mammadli’s case and added: “For us, economic development and greater prosperity go along with greater human rights.” U.S. Secretary of State John Kerry congratulated President Aliyev on the FID and described it as “a symbol of an important milestone in Azerbaijan's history ... By making the first step in joining Europe, Azerbaijan is becoming a new reliable member of world energy resources and helps ensure Europe’s energy security,” he noted in a statement published on the website of the U.S.-Azerbaijan Chamber of Commerce on January 7.