A retired colonel reputed for constant criticism of the Nigerian government's handling of the Boko Haram insurgency has reportedly been arrested and kept incommunicado by the secret police.

Activists and family friends told Anadolu Agency that retired army colonel Husseini Monguno was arrested on Feb. 13 shortly after he granted a media interview reviewing Nigeria's counterinsurgency strategies in the country's northeast.

“They have since kept him incommunicado. Family members and his lawyer have had no access to him, while members of his immediate family are being threatened to remain silent,” Fulan Nasrullah, a security expert and family friend to Monguno, told Anadolu Agency on Saturday.

“The DSS (Directorate of State Security, or the secret police) despite enquiries have refused to formally confirm that they hold him, but informally they have sent emissaries to threaten the family to not talk to the press or make noise about his detention,” Nasrullah added.

He said no formal charges have been brought against him.

An online campaign titled #FreeHusseiniMonguno gained momentum on Twitter on Saturday, with activists flaying what they called a resort to draconian measures to silence critics of the government.

Dan Borno, another prominent online personality, condemned on Saturday the continuous detention of the retired soldier.

“Arrest without trial is undemocratic. The government should free Husseini Monguno or charge him to court,” the activist said.

Anadolu Agency’s attempt to speak with his wife proved abortive.

Monguno has repeatedly decried government’s claim of having “technically defeated Boko Haram”, although his criticism of government’s handling of the insurgency dated back to the Goodluck Jonathan years.

The Nigerian government has claimed technical defeat of the militants but analysts like Monguno insist such claim is far-fetched in the face of continuous bombings and attacks on civilian targets in remote villages.

Monguno has also accused army authorities of always downplaying or denying the killing of soldiers by militants.

Spokesman of the secret police Tony Opuiyo could not be reached for comment. (Anadolu Agency)