Young people protesting the arrest of Mathira MP Rigathi Gachagua on Friday blocked parts of the Nyeri-Nairobi highway.
Anti-riot police officers were deployed to quell the protest.
"As predicted two dozens of DCI officers raided my Nyeri home and arrested me to face trumped-up charges of money laundering. I am being driven to Nairobi at reckless speed to spend the weekend in the cells," the MP posted on his social media page.
Last month, detectives said they have finalised investigation into tenders involving companies associated with Mr Gachagua, putting the legislator in trouble over Sh12 billion said to have passed through his accounts.
The number of companies associated with the MP’s transactions, and those of his proxies, have now reached 40, revealing what seems to be a complex web of transfers.
Most of the transfers end up in a company known as Wamunyoro Investments Limited, where Mr Gachagua and his wife, pastor Dorcas Wanjiku, are the only shareholders.
“We have completed that investigation and it has taken us a lot of time,” said Director of Criminal Investigations George Kinoti, without revealing his next move.