A young widow has tearfully demanded an inquiry into how a psychotic man was free to kill the father of her newborn baby days after knife and assault charges against him were dropped.
Dr Jeroen Ensink, 41, was stabbed to death as he left his flat in Islington, north London, to post cards announcing the birth of his daughter Fleur 10 days before.
When the renowned academic failed to return, his wife, Nadja, went outside to find police had cordoned off the street and the cards her husband had been carrying strewn on the pavement spattered with blood.
Prosecutor Duncan Atkinson QC said the victim shouted for help and said "no, not a knife", before the ferocious attack by a barefooted Femi Nandap.
The 23-year-old student stabbed Dr Ensink repeatedly in the chest and back until an off duty special constable intervened.
The defendant, who was born in Nigeria, told psychiatrists that he started to receive telepathic messages and considered himself the "chosen one" or "Messiah" in spring last year.
Just six days before he attacked Dr Ensink, the London School of Economics student had charges of possession of a knife and assaulting a police officer dropped at magistrates' court.
The charges related to an incident in May last year when Nandap was seen in Primrose Gardens, north west London, with a 30 inch kitchen knife and punched and bit an officer who was trying to arrest him.
While on conditional bail he went to Nigeria where he was treated for mental illness but he stopped taking anti-psychotic drugs by his return to the UK in October.
On August 25, his sister had handed a letter to police explaining he was not fit to travel back to the UK earlier because he was suffering "depression and psychosis".
Mrs Ensink-Teich went to the Old Bailey with her baby daughter to see Nandap sentenced for killing her "soul mate".
Reading her victim impact statement in court, she demanded in independent investigation into failings by both the mental health service and legal system.
She told the court: "Not only was the love of my life taken from me, but with him also all of our hopes and dreams."
The circumstances surrounding the death of her husband were not a "one off", Mrs Ensink-Teich said.
She said: "This is a terrible tragedy for me and for Jeroen's daughter, and family and friends but it is not a one off; mental health homicides keep happening again and again.
"If such tragedies keep occurring, why has there not been concerted action to address this?
"If a person with a history of mental health problems is found wandering about with a knife, and attacks a police officer, then that person must be referred to a secure unit for proper assessment and treatment and not given bail so easily.
"This represents a failure of the health and judicial system that should protect the public and care for those with severe mental illness."
An inquiry should look into how Nandap was granted bail after being charged with assaulting an officer and wielding knifes in public and why he was free on the day of the killing, the court heard.
She said an inquiry should examine why the Crown Prosecution Service dropped the earlier charges and deal with whether the person responsible for the decision will be held accountable.
She went on: "This may help others from being in the same position my daughter and I now find ourselves in. I hope that our case highlights the necessity to bring about the required changes to existing laws. Lessons will not have been learned until concrete changes in legislation will be implemented."
At an earlier hearing, Nandap, of Woolwich, south-east London, admitted the manslaughter of Dr Ensink by reason of diminished responsibility via video link from Broadmoor hospital.
Dr Ensink, originally from the Netherlands, worked at the London School of Hygiene and Tropical Medicine.
He was a renowned water engineer and a dedicated humanitarian who was committed to improving access to water and sanitation in deprived countries.
Judge Nicholas Hilliard QC said he was on any view a "truly remarkable" man.
Dr Ensink's manager Sandy Cairncross said: "He was killed in his prime and just as he was getting his own research projects under way, with potential benefits to millions of people."
Mr Atkinson said the timing of events had raised "a justifiable sense of concern" and there had been learning points following a review at the "highest level".
It was now recognised the decision making was "not as it should have been". The issues include monitoring those on bail and identifying "at an earlier stage" those with mental health difficulties, he said.
Nandap faces a potential hospital order or a hybrid order which would allow for the possibility of being later transferred to jail.
The court heard that Nandap had been in the UK on a student visa which had expired by the time of the killing.
At the conclusion of any hospital order he will face deportation back to Nigeria, the court heard.
Dr Samrat Sengupta, from Broadmoor hospital, told the court that smoking cannabis had triggered a genetic psychotic illness.
When asked by Judge Hilliard how smoking a "large amount" of the drug had affected Nandap, the doctor said: "Cannabis can give rise to generally two forms of psychotic disorder. One is relatively relievable by withdrawing the substance. The second is much more dangerous, which triggers off an enduring psychotic illness.
"In my view he has developed the latter type of this illness."