Busia Senator Okiya Omtatah was arrested alongside other protesters during a demonstration in Nairobi against rising cases of abductions and enforced disappearances.
The group, which had chained themselves together along Aga Khan Walk, was dispersed by police and taken into custody.
Omtatah is reportedly held at Gigiri Police Station for questioning.
Activists claim over 80 abductions have occurred this year, with more than 10 in December alone.
Among the missing are activists who shared satirical content about President William Ruto.
Human rights groups demand action and accountability from the government.
