Police have given conflicting accounts of his whereabouts.
While police maintain that lawyer was nabbed drunk, a battery of human rights activists say he was drugged and arrested while in critical condition, a sensational claim which Nairobi police boss Japheth Koome disputed.
Mr Koome told a local daily Monday morning that he (Mr Ndubi) was arrested at 8.45pm on Jakaya Kikwete Road, in the capital Nairobi and that he was driving under the influence of alcohol.
“He parked the vehicle in the middle of the road…he slept in the vehicle…[he was] very drunk,” Mr Koome said as quoted by the Nation.
He added: “He was arrested. He is in custody, and he is going to court this morning for driving under the influence of alcohol.”
On Sunday night, activist Alamin Kimathi tweeted that Mr Ndubi was drugged near State House and police arrested him “instead of taking him to hospital”.
He said the lawyer was “in critical condition at Kileleshwa Police Station”.
Mr Koome did not confirm in which police station the lawyer was being held, but maintained the lawyer was not drugged. He added that Mr Ndubi was conscious.
Mr Kimanthi claimed that police had been ordered not to produce Mr Ndubi in Kibera Law Courts Monday morning, terming it a complicated matter.
“This Harun Ndubi story is becoming totally absurd. Police at Kileleshwa police station say they were ordered this morning not to take him to Kibera law courts and have been told to take him to Kilimani police station instead,” he tweeted.