Feisty lawyer and Nasa operative's whereabouts are unknown.
Kenyan firebrand opposition member Miguna Miguna has been arrested in a dawn raid at his home in the posh Runda suburb of Nairobi.
The self-declared general of the newly outlawed Nasa's National Resistance Movement (NRM) Friday morning told Nation that police had stormed into his house and ransacked it.
“The police have bombed their way into my house. I can't speak on the phone right now. They have ransacked the house!!” Mr Miguna said in text message sent to a Nation editor.
Armed officers used explosives to break down the door before arresting Mr Miguna, a witness told AFP.
"There were several blasts heard at his home before he was finally taken out," said a neighbour who did not want to be named.
The Director of Criminal Investigation George Kinoti confirmed the raid saying Mr Miguna was arrested for administering an illegal oath and being a member of a proscribed organisation.
“He publicly declared that he is the general of NRM, which is already declared a proscribed group. By the time he declared publicly, there was a gazette notice by the minister. How can we let it go? We are law enforcers,” said Mr Kinoti.
“He also said he is going to lead people to burn portraits of a democratically elected president. Then what do you expect from us?
"He also confessed he is the one who administered the oath,” the DCI boss added.
Miguna is a lawyer and a rabble-rouser who attended the Tuesday mock swearing-in of opposition National Super Alliance (Nasa) leader Raila Odinga as the "people's president", in defiance of last year's election that saw Uhuru Kenyatta win a second term.
On Thursday he goaded police, daring them to arrest him saying he had signed Mr Odinga's oath, "So if you want to take me to court for doing my job, come baby come!"
Police sources confirmed that Mr Miguna was taken to Kiambu Police Station, a few kilometres north of the capital Nairobi, but was later driven off to an unknown destination.
Mr Miguna's arrest follows that of TJ Kajwang, a lawyer and MP who was arrested on Wednesday and is due to be charged with treason and unlawful assembly.
Both men played prominent roles in the mock swearing-in, flanking Odinga as he took an oath while clutching a Bible, Miguna is his trademark kufi cap and Kajwang in a judge's robe and wig.
Their presence was particularly important given the absence of all three of Mr Odinga's partners in the Nasa coalition.
While Mr Miguna lost in his bid to become governor of Nairobi last year and holds no official position within Nasa, he is the self-styled "general" of the party's NRM wing which is tasked with implementing a threatened programme of civil disobedience and boycotts.
Following Mr Odinga's pretend inauguration Kenya's government designated the NRM as an "organised criminal group".
Friday's arrest is the latest twist in the long saga of Kenya's disputed elections which saw the Supreme Court annul the result of the initial August poll and Mr Odinga boycott the October rerun.
Mr Odinga insists he is the real winner and therefore the legitimate president of Kenya.
-Reporting by Nation reporters and AFP.