Arturo Cruz was detained after the opposition presidential candidate Christiana Chamorro was placed under house arrest for three days.

The Nicaraguan police detained the opposition politician Arturo Cruz, detained the second presidential candidate in less than a week, and in November President Daniel Ortega sought to maintain his power. Control the election before escalating the battle.

According to his assistants, Cruz is an academic who served as Nicaragua’s ambassador to the United States from 2007 to 2009, and was detained after arriving at Managua Airport from Washington DC on Saturday.

The prosecutor’s office said in a statement that the national police is investigating Cruz on the grounds that “he attacked Nicaraguan society with strong evidence”.

It did not specify the possible charges against the 67-year-old man, nor whether he will continue to be detained or arrested.

Cruz was taken into custody after the opposition figure Cristiana Chamorro-also a possible challenger for Ortega in the November election-was placed under house arrest for three days after the government claimed that she was guilty of money laundering.

Cruz was a former ally of Ortega. He was a candidate for the Alianza Ciudadana or Citizen’s Alliance, a right-wing coalition supported by well-known businessmen to participate in the November presidential election.

The Nicaraguan Human Rights Center described the detention of Ortega’s government as an “abnormal strategy” designed to silence people he considers to be political enemies.

“These are not criminal investigations, they are political persecution,” it said.

This we Called on Cruz to “release immediately.”

Acting Deputy Secretary of the Western Hemisphere Affairs Bureau of the US State Department Julie Zhong said on Twitter: “The international community has already said: Under Ortega’s leadership, Nicaragua is becoming an international untouchable and is getting farther and farther away from democracy.”

The Organization of American States also urged the Nicaraguan authorities to release Cruz.

The Secretary-General of the Organization of American States Luis Almagro said on Twitter: “Manipulating the security forces and the judiciary to imprison opposition candidates is unacceptable… These actions are contrary to free and fair elections.”

Ortega is a former guerrilla who was in power from 1979 to 1990, returned to power in 2007, and was re-elected twice. The 75-year-old aims to be re-elected for the third consecutive term in November.

International organizations including the Inter-American Commission on Human Rights and the Office of the United Nations High Commissioner for Human Rights accused the Ortega government of fabricating false accusations against opponents.

The electoral agency has eliminated two opposition parties.