A man who was stabbed to death days after Christmas has been named as Dr Jeroen Ensink, a lecturer at the London School of Hygiene and Tropical Medicine.
Dr Ensink, 41, was found suffering from stab wounds following an incident in Hilldrop Crescent, Islington, north London, on December 28. He was pronounced dead at the scene shortly after 1.50pm.
His colleagues have paid tribute to the "popular" public health lecturer, saying he will be "greatly missed".
Professor Peter Piot, director of the London School of Hygiene and Tropical Medicine, said: "We are deeply shocked and saddened by the death of Jeroen Ensink.
"Jeroen was passionately committed to a simple cause: improving access to water and sanitation in countries where children continue to die needlessly due to the lack of these basic services."
Dr Ensink joined the school almost a decade ago, and at the time of his death he was was leading a large study in the Democratic Republic of Congo to understand how improvements in water supply could control and prevent cholera outbreaks.
Prof Piot added: "He was a natural educator and immensely popular with students in whom he invested much time and energy; he provided support and inspiration in equal measure and many of his students are now successful researchers and public health professionals in their own right.
"Jeroen will be greatly missed by all the staff and students who had the opportunity to know and work with him, and the legacy of his work will continue in Asia and Africa.
"Our deepest condolences go to his family and friends."
Timchang Nandap, 22, of Pett Street, Woolwich, south-east London, has been charged with Dr Ensink's murder.
He appeared at Highbury Corner Magistrates' Court today, and was remanded in custody to appear at the Old Bailey on January 4, Scotland Yard said.