The prominent clinical psychologist and mental health researcher was shot dead by gunmen on a motorbike.

The Directorate of Criminal Investigations (DCI) has launched investigations into the fatal shooting of prominent clinical psychologist and mental health researcher Dr Victoria Nthunya Mutiso, who was killed on Wednesday morning in Nairobi's Upper Hill area.

In a statement, the DCI pledged to conduct a thorough, impartial and professional investigation to establish the circumstances surrounding the killing and bring those responsible to justice.

"Detectives recovered and documented forensic exhibits for analysis, interviewed witnesses and also visited the medical facility where the victim had been taken," DCI said in a statement.

Mutiso was shot dead by gunmen on a motorcycle and died at Kenyatta National Hospital, where she was rushed after the attack.

Eyewitnesses said the researcher was in a taxi when the gunmen on a motorcycle struck and opened fire after the taxi was blocked by another vehicle.

Preliminary investigations indicate that Dr Mutiso had requested an Uber ride for transport when she sustained fatal gunshot injuries under circumstances that remain under investigation.

"Investigators are pursuing all critical leads, including persons of investigative interest," the statement added.

The DCI urged members of the public to refrain from speculation or sharing unverified information, warning that such actions could compromise ongoing investigations.

Anyone with information that may assist in the investigations has been urged to report to the nearest police station or anonymously through the DCI's Fichua Kwa DCI platform by calling the toll-free number 0800 722 203 or sending a WhatsApp message to 0709 570 000.