An opposition leader in Equatorial Guinea who was arrested and held for three days inside a prison was released late Friday.

Marcial Abaga Barril, the representative of the main opposition party on Equatorial Guinea's national election body, was taken into custody on Nov. 1 allegedly in connection with a murder investigation.

His arrest came as his party was preparing to hold a public event to urge a "no" vote on this month's constitutional referendum, which if passed would all but ensure that the country's leader would be able to rule for at least 14 more years.

In an email to The Associated Press, New York-based Human Rights Watch confirmed that Abaga had been released Friday afternoon. "At the moment, his No. 1 priority is having a shower and being with family," the email said.

President Teodoro Obiang Nguema has ruled Equatorial Guinea, a tiny, oil-rich nation located south of Senegal off the western coast of Africa, for 32 years since seizing power in a 1979 coup. The proposed constitutional changes would allow him to run for two more seven-year terms, all but ensuring Obiang will extend his grip on power into a fifth decade. The Nov. 13 referendum also asks voters to approve the position of vice president, a post that would be directly appointed by the president.

Obiang's son, Teodorin Obiang Mangue, has already been named vice president of the ruling party, heightening speculation that the elder Obiang is attempting to change the constitution in order to assure a father-to-son succession.

"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 in the statement released late Thursday. "The allegation that Abaga is connected with a murder simply has no credibility."

Family members told Human Rights Watch that Abaga was detained outside his home at around 10 p.m. on Tuesday night. He was taken to a Malabo jail nicknamed "Guantanamo," where in the past opponents of the regime have been brutalized.

It was only on the afternoon of Nov. 2 _ more than 12 hours after he was detained _ that he was told he was being held into the alleged killing last month of a cook working for Obiang, people close to Abaga told the rights group.

Equatorial Guinea's opposition is small, consisting of only two political parties that are independent of the governing party. Most neighboring nations have over 100 opposition parties. Considered one of the most repressive regimes in Africa, the Obiang government is accused of using brutal tactics, including torture through electroshocks administered to the body via alligator clips, to silence opponents.

In the lead-up to the Nov. 13 poll, police have disrupted events held by Abaga's party, the Convergence for Social Democracy, or CPDS, according to EG Justice, a U.S.-based group advocating for rule of law and human rights in Equatorial Guinea.

Last month, the United States Department of Justice revealed they are attempting to seize assets worth $70 million that the younger Obiang transferred to the United States and used to buy a Malibu mansion, a Gulfstream jet and $2 million worth of Michael Jackson memorabilia.