A pick-up truck transporting Miraa from Meru to Liboi was hijacked by alleged Al Shabaab militia members near Liboi town on Sunday night.
The car, which had three passengers, was later seen crossing into Somalia near Dagalema.
North Eastern Regional Police Commander David Bunei confirmed the 8:30 p.m. incident.
Abdikaddir Hassan Elmi, a driver, Abdullahi Issak Harun, a Miraa dealer, and Habiba Abdi Sirat, who had hiked a lift, are among those who have been released.
This incident comes after Kenya Army soldiers in Gumurey, Wajir North captured a unspecified number of Al-Shabaab Mujahideen terrorists and killed several others.
The soldiers were confronted by the militants, who had staged an assault targeting a patrol unit.