Sharon was romantically linked to Migori governor Okoth Obado. She was 7-months pregnant with a baby boy for the governor.
Today morning, Migori governor Okoth Obado's bodyguard was arrested outside the Milimani law court.
Citizen TV showed detectives putting handcuffs on John Chacha after taking away his gun.
Chacha is to be taken to the Directorate of Criminal Investigations offices for questioning.
He was arrested when Obado was already in court to face charges of aiding, abetting, and financing the murder of Rongo university student Sharon Otieno.
Obado arrived in court on Monday after spending three nights at the Gigiri police cells.
Sharon, who seven-months pregnant at the time of her abduction, was found dead in Kodera Forest on September 5.
The postmortem revealed she was raped and stabbed eight times; three times in the neck, four times in the back, and on the left side of her abdomen.
On Sunday, DPP Noordin Haji directed the DCI to pursue and arrest the hit men in the murder of Sharon.
"Ensure that the hit men and other persons who have been adversely mentioned are arrested," Haji said in a statement on Sunday.