Thirty-eight Kenya Revenue Authority employees who were locked up for 14 days have filed an application at the High Court challenging their detention.
On Monday, a court had ruled that the KRA staff remain in custody for two weeks as detectives probe a tax evasion scandal.
Another 30 workers have also been arraigned with police seeking to have them detained for 21 days.
Four other suspects who were summoned to the Directorate of Criminal Investigations for questioning are seeking anticipatory bail ahead of probable arrest and prosecution.
They are Mr Joseph Kuyo Legei, Mr Geoffrey Kipsang Ngeno, Mr Felix Ndambuki Kimeu, and Mr Caleb Angwenyi Auka.
They have filed a suit against the Attorney-General and the Director of Public Prosecution, claiming that a tweet by the DCI on May 12, summoning them for questioning on May 15, also alluded that they were involved in the scandal that has rocked the taxman.
They argue that they were "confused" to have committed certain crimes which were not made known but would nevertheless availed themselves for questioning. They also protested use of social media to issue the summons.
“According to Section 52 of the National Police Act, a notice compelling attendance to a person should be given to the intended person in writing and accordingly, the Penal Code consequence intended by Section 52 do not flow by way of social media,” lawyer Morris Kimuli said.
According to the lawyer, his clients are apprehensive that they may face unlawful detention.
“In the above circumstances, it is necessary in the interest of justice that this court grants us anticipatory bail pending arrests and charge by the state,” they said.
Last Friday, 70 KRA staff were arrested but only 38 appeared were arraigned before Senior Resident Magistrate Paul Mayova.