NAIROBI (Reuters) - Police in Burundi arrested an American journalist and her Burundian fixer on Sunday, saying they had questioned both on suspicion of destroying criminal evidence before releasing only the journalist from custody.

Julia Steers, a fellow with the International Women’s Media Foundation, and Gildas Yihundimpundu were arrested in the Mutakura district north of the capital Bujumbura, police spokesman Pierre Nkurikiye wrote on his Twitter account.

The media regulator “CNC and police interrogated them for attempting to destroy evidence of crimes committed by insurgents,” the tweet said. The government often uses the term “insurgents” to describe protesters.

Mutakura was hit by protests at the height of the unrest last year when President Pierre Nkurunziza announced plans to run for a third term in office, sparking weeks of protests by the opposition who said his bid was unconstitutional.

Nkurikiye said the journalist has subsequently been released and handed to the U.S. embassy, but her fixer remained under custody for further investigation.

Opponents accuse the president of violating the constitution and a peace deal that ended a civil war in 2005. The government accuses opponents of fomenting unrest, and accuses them of backing rebel groups, which officials call “armed gangs”.

At least 450 people have so far been killed in violence that first erupted right after Nkurunziza announced his re-election bid, rights groups say.

Western states have also criticized the government’s clampdown on free media, including the shuttering of private radio stations.

Burundi briefly arrested British and French journalists earlier this year, while other foreign journalists were expelled prior to that.