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Kenyan wanted for girlfriend's murder in UK arrested, faces extradition to London

Brian Kiprop Kiplagat, who allegedly killed his girlfriend, Marianne Kilonzi(inset), in January 2025 detained in Kenya pending extradition to London to face a murder charge.

Photo credit: Richard Munguti| Nation Media Group

A Kenyan man living and working in Britain who allegedly killed his girlfriend in January 2025 before fleeing to Kenya has been detained in custody pending extradition to London to face a murder charge.

Brian Kiprop Kiplagat, who was arrested on June 10, 2026, at the Namanga border post while allegedly attempting to flee to Tanzania, is said to be a flight risk.

The Director of Public Prosecutions (DPP), Renson Ingonga, through prosecuting counsel, urged a senior principal magistrate at the Milimani Law Courts to detain Kiplagat for 21 days as the government secures relevant documentation and information from London ahead of his extradition to face a murder charge contrary to Section 203 as read with Section 204 of the Penal Code.

Prosecuting counsel Joyce Olajo told the magistrate that Kenya and Britain have a signed extradition treaty covering fugitives.

Ms Olajo stated that the application to detain Kiplagat was made under Article 49(1)(f) and (g) of the Constitution of Kenya, 2010, and Section 36A of the Criminal Procedure Code, Chapter 75 of the Laws of Kenya, which allows courts to grant police additional time to hold a suspect pending investigations and prosecution.

The magistrate heard that Kiplagat was allegedly involved in the murder of his girlfriend, Maryanne Nduta Kilonzo, a career banker who lived and worked in London.

Marianne Kilonzi

Marianne Kilonzi

Photo credit: Pool | Nation

“Equally, murder is an offence in Kenya just as it is in Britain under Section 203 as read with Section 204 of the Penal Code, Chapter 63 of the Laws of Kenya,” Ms Olajo told the court.

The prosecutor noted that Kenya, a former British colony, inherited many of the laws currently applicable in the country.

“The suspect herein is a flight risk, having been arrested at the Namanga Border Post by police officers attached to the Immigration Office. I therefore urge the court to deny him bond and direct that he be detained at the Anti-Terrorism Police Unit (ATPU) due to the seriousness of the offence,” Ms Olajo submitted.

The prosecution stated that after the alleged murder, the suspect sent a text message to one of the deceased's relatives, describing Maryanne's death as a misfortune.

Police believe the suspect still possesses the phone used to send the message, which is required for forensic examination and extraction of information.

“The United Kingdom, through the Metropolitan Police Service, requested assistance from Kenyan authorities in locating and arresting the suspect, believing that he had entered Kenyan territory,” the prosecutor stated.

The magistrate was told that police detectives and undercover officers had been tracking the suspect.

“On Wednesday, June 10, 2026, at about 3 p.m., the suspect was intercepted at Namanga by immigration officers while using a temporary permit issued on the same day,” the court heard.

DNBRIANKIPROP1806(1)

Brian Kiprop, who is alleged to have killed his girlfriend, Marianne Kilonzi, in January 2025 in the United Kingdom, appeared at the Milimani law court on June 18, 2026. Magistrate Daisy Mutai ruled that he should be detained for 7 days as detectives complete investigations into the matter. 

Photo credit: Billy Ogada | Nation

The permit bore the number TP-JDUK67EL. Kiplagat was reportedly heading to Tanzania.

At the time of his arrest, he was in possession of Kenyan passport number CK84104.

Urging the court to detain the suspect, the prosecution argued that Kiplagat “has no fixed abode, having been moving between different locations within the country.”

The UK authorities requested Kenyan police to arrest the suspect and facilitate his extradition to London, where he is wanted in connection with the alleged murder.

The magistrate was also informed that the suspect possesses several travel documents, some of which are suspected to have been obtained fraudulently.

The prosecution said it is yet to receive a formal extradition request from the UK through the Ministry of Foreign Affairs.

Once received, the request will be forwarded to the Office of the Attorney General, which will then transmit the necessary documents to the DPP for presentation before the court.

In the meantime, the magistrate ordered that the suspect remain in custody until June 15, 2026, when the matter will be mentioned for further directions.