"He was freed before Tet (Lunar New Year) and because his mother's health is poor," said Dang Ngoc Anh, the sister-in-law of lawyer Le Cong Dinh, 44.

Dinh was one of four democracy activists convicted in January 2010 at a day-long trial in southern Ho Chi Minh City that was was condemned by human rights groups and the European Union.

Dinh, whose sentence also included three years of house arrest after his release from prison, had been detained since June 2009.

Dozens of activists have been jailed since Vietnam a one-party state that forbids political debate began a new crackdown on free expression in late 2009.

According to New York-based Human Rights Watch, Vietnam jailed at least 33 activists in 2012 based on vaguely defined articles in its penal code that criminalise the exercise of civil and political rights.

On Monday Vietnam sentenced 22 activists to lengthy jail terms ranging from 10 years to life imprisonment, after one of the country's largest subversion trials for years. Rights groups say charges of spreading anti-state propaganda and attempting to overthrow the regime are routinely laid against peaceful dissidents in Vietnam.

Agence France Presse - February 6, 2013