The High Court has ordered suspects Jacque Maribe and her fiancé Joseph Irungu detained until Monday after a mental assessment was ordered for the television journalist.
Ms Maribe will undergo the test at Mathari Hospital in Nairobi. Justice Jessi Lessit said the suspect cannot be called upon to plead to charges without a mental examination.
The two suspects were presented in court on Tuesday morning and were seen furtively communicating in the dock.
Mr Irungu, chewing gum and his hand in a sling, will also get treatment for his gunshot wound.
His lawyer told the court that the arm is paralysed and swollen as he produced a referral note from Nairobi Hospital to Kenyatta National Hospital.
During an interview with NTV, Mr Irungu's parents said police officers had denied him access to medical treatment since his arrest.
The Director of Public Prosecutions Noordin Haji ordered their trial over the murder of Monica Kimani, who was killed in her house in Kilimani, Nairobi, on September 19
In the court, Ms Maribe was seen speaking with her mother as she and Mr Irungu waited for the court proceedings to start.