Abaga’s arrest and detention comes just days after the start of campaigning for a Nov. 13 referendum to approve constitutional changes proposed by President Teodoro Obiang’s government. Abaga’s party has strongly opposed the constitutional changes. Sources close to him said that on the day of his arrest he had been helping to plan a series of public events to press for a “no” vote on the referendum.

“Marcial Abaga’s politically motivated arrest is yet another example of President Obiang’s offensive against opposition voices,” said Daniel Bekele, Africa director at Human Rights Watch. “The allegation that Abaga is connected with a murder simply has no credibility.”

The Obiang government has sought to silence those opposed to the referendum. Uniformed police officers and others in plainclothes disrupted events held this week by Abaga’s party, Convergence for Social Democracy (Convergencia Para la Democracia Social, CPDS), and forced the participants to disperse, a witness told EG Justice, a US-based group that works for human rights and the rule of law in Equatorial Guinea. Abaga is on the party’s national executive committee. It is one of only two political parties in the country that are independent of the governing party. He is a municipal council member in Malabo and also sits on the National Electoral Commission of Equatorial Guinea as the representative of his party. The electoral body, which is dominated by the ruling Democratic Party of Ecuatorial Guinea (Partido Democrático de Guinea Ecuatorial, PDGE) and representatives of allied parties, lacks the independence necessary to oversee votes impartially, Human Rights Watch and EG Justice said.

Human Rights Watch and EG Justice emphasized that there is no independent judiciary in Equatorial Guinea. The government commonly carries out arbitrary arrests and denies detainees due process, holding them indefinitely without telling them the charges against them. Basic fair trial standards are disregarded. Torture remains a serious problem despite a national law prohibiting it. Abaga has not reported being ill-treated, according to the sources.

The constitutional changes coming up for a November 13 vote would potentially allow 69-year-old Obiang to serve for two more terms of seven years each. They also would create a new post for a hand-picked vice president, widely considered to be intended for his eldest son, Teodoro Nguema Obiang Mangue, who is his presumed successor. The younger Obiang has been the subject of corruption and money-laundering investigations in France, Spain, and the United States. These investigations have so far led to the seizure of a fleet of luxury vehicles outside his Paris residence and a US government effort to seize more than $70 million in assets.

In October, the president appointed the younger Obiang, known as Teodorín, to head the ruling party’s campaign to promote the referendum. In 2010, Teodorín was made the vice president of the ruling party.

Equatorial Guinea has been roundly criticized for its conduct of elections. President Obiang was re-elected in November 2009 with 95.4 percent of the vote in an election with weak international monitoring, raising “the suspicion of systematic voting fraud,” according to the US State Department. Ahead of the vote, the government stifled and harassed the country’s beleaguered political opposition, denied the opposition equal access to the media, and imposed serious constraints on international observers. Abaga also is active as the head of a youth organization engaged in human rights education, Sensation of the Young Future (Sensación del Joven Futuro, SEJOF). And he is an advocate for greater transparency about the government’s management of oil revenue through participation in the international Publish What You Pay Coalition and the now-defunct National Commission for the Extractive Industries Transparency Initiative (EITI). Equatorial Guinea was a candidate country for membership in EITI until 2010, when it was expelled from the initiative.

Abaga was detained outside his home at approximately 10 p.m. on November 1, by plainclothes security officials who said they were from the police but did not provide an explanation for the arrest other than to say they needed to question him as part of an investigation, a family member said. He was taken to the Malabo jail known as “Guantánamo” because of its reputation for abuses against detainees, where he has had access to visits from family members, colleagues, and his lawyer. Equatorial Guinea’s law allows for a suspect to be held in detention without charge for up to 72 hours. Sources close to Abaga said he was informed on the afternoon of November 2 – more than 12 hours after he was detained – that he was being held in connection with a police investigation into an alleged killing two weeks earlier of a cook working for President Obiang. No such incident had previously been publicly reported. Abaga firmly denies the allegation, which Human Rights Watch and EG Justice described as implausible.