Slain lawyer Willie Kimani made desperate attempts to reach his family after he was locked at Syokimau police station, the court has been told.
Mr Kimani was found dead along with his client Josphat Mwenda and taxi driver Joseph Muiruri in 2016, a case that shocked the country.
Chief Inspector Robert Owino on Monday said the slain lawyer wrote a note on a tissue paper and threw it outside the police station for help.
The piece, the court heard, was picked by a bodaboda rider with attempts to reach the family of the slain lawyer but in vain.
Kimani's wife, the court was told, thought the call was from conmen but the reality would hit hours later when her husband failed to return home.
“On June 27, 2016, we received a report from document examiner that the note was written by late Willie Kimani which confirmed that they were confined in a fabricated container," Owino said.
"The note had indicated that the three had been detained at the AP Camp and they were asking for assistance as they feared their lives were in danger,” narrated Owino.
The bodies of the three were discovered hours later. Five suspects are currently battling with the prosecution in court over the gruesome murder.
Justice Jessie Lessit adjourned the trial to November 25th when more witnesses are expected to be interrogated by both the prosecution and defence.
The murder case has attracted keen interest from lawyers, who have often clashed with their colleagues representing the murder suspect.