The Standard newspaper correspondent for Bondo was arrested on Wednesday night by officers from the Quick Response Team (QRT) who allegedly assaulted him.
Gwengi was apprehended alongside rights activist Rodgers Ochieng’. Following their release, they were taken to Bondo referral hospital.
Police denied assaulting the two but the journalist said his private parts were severely squeezed.
Narrating the ordeal shortly after the release, Gwengi said he was on his way home from work when four QRT officers approached.
"They asked for my phone before ordering me to follow them. I reluctantly followed their orders."
"I was slapped in the face, forced into a waiting police vehicle and taken to Usenge AP post where I was thoroughly beaten," Gwengi said.
The officers threatened to shoot us at close range, he added.
Gwengi said he had recorded a statement at Bondo DCIO in January after an officer attached to the QRT threatened him.
The journalist said they were "tortured" for about four hours by officers who used gun butts and clubs. He said he was also strangled.
Police accused Gwengi of inciting the public through his articles.
Ben Mandere, Siaya county AP commandant, said he was told the two had been inciting members of the public to turn against officers.
He said Gwengi had written several negative stories about the QRT with the intention of portraying it as inept and corrupt, a situation he said made the public lose confidence in the unit.
Ochieng' said they tried to secure their release by pleading innocent but the officers did not listen to them.
He said that after they were beaten, they were taken to Usenge police station where they were to be held in custody but the officers at the station declined because of their injuries.
They were then taken to Got Agulu dispensary for check-ups.
-The Star