On 16th December 1910, a gang that is believed to included Smoller, Svaars, Gardstein, Peter Piaktow (Peter the Painter), Yakov Peters, Yourka Dubof, Karl Hoffman, John Rosen and William Sokolow, attempted to break into the rear of Henry Harris's jeweller's shop in Houndsditch, from Exchange Buildings in the cul-de-sac behind. The Daily Telegraph reported: "Some two or three weeks ago this particular house in Exchange Buildings was rented and there went to live there two men and a woman. They were little known by neighbours, and kept very quiet, as if, indeed, to escape observation. They are said to have been foreigners in appearance, and the whole neighbourhood of Houndsditch containing a great number of aliens, and removal being not infrequent, the arrival of this new household created no comment. The police, however, evidently had some cause to suspect their intentions. The neighbourhood is always well patrolled. Shortly before 11.30 last night there were sounds either at the back of these newcomers' premises or at Mr Harris's shop that attracted the attention of the police."

A neighbouring shopkeeper, Max Weil, heard their hammering, informed the City of London Police, and nine unarmed officers arrived at the house. Sergeant Robert Bentley knocked on the door of 11 Exchange Buildings. The door was open by Gardstein and Bentley asked him: "Have you been working or knocking about inside?" Bentley did not answer him and withdrew inside the room. Bentley gently pushed open the door, and was followed by Sergeant Bryant. Constable Arthur Strongman was waiting outside. "The door was opened by some person whom I did not see. Police Sergeant Bentley appeared to have a conversation with the person, and the door was then partly closed, shortly afterwards Bentley pushed the door open and entered."

According to Donald Rumbelow, the author of The Siege of Sidney Street (1973): "Bentley stepped further into the room. As he did so the back door was flung open and a man, mistakenly identified as Gardstein, walked rapidly into the room. He was holding a pistol which he fired as he advanced with the barrel pointing towards the unarmed Bentley. As he opened fire so did the man on the stairs. The shot fired from the stairs went through the rim of Bentley's helmet, across his face and out through the shutter behind him... His first shot hit Bentley in the shoulder and the second went through his neck almost severing his spinal cord. Bentley staggered back against the half-open door and collapsed backwards over the doorstep so that he was lying half in and half out of the house."

Sergeant Bryant later recalled: "Immediately I saw a man coming from the back door of the room between Bentley and the table. On 6 January I went to the City of London Mortuary and there saw a dead body and I recognised the man. I noticed he had a pistol in his hand, and at once commenced to fire towards Bentley's right shoulder. He was just in the room. The shots were fired very rapidly. I distinctly heard 3 or 4. I at once put up my hands and I felt my left hand fall and I fell out on to the footway. Immediately the man commenced to fire Bentley staggered back against the door post of the opening into the room. The appearance of the pistol struck me as being a long one. I think I should know a similar one again if I saw it. Only one barrel, and it seemed to me to be a black one. I next remember getting up and staggered along by the wall for a few yards until I recovered myself. I was going away from Cutler Street. I must have been dazed as I have a very faint recollection of what happened then."

Constable Ernest Woodhams ran to help Bentley and Bryant. He was immediately shot by one of the gunman. The Mauser bullet shattered his thigh bone and he fell unconscious to the ground. Two men with guns came from inside the house. Strongman later recalled: "A man aged about 30, height 5 ft 6 or 7, pale thin face, dark curly hair and dark moustache, dress dark jacket suit, no hat, who pointed the revolver in the direction of Sergeant Tucker and myself, firing rapidly. Strongman was shot in the arm, but Sergeant Charles Tucker was shot twice, once in the hip and once in the heart. He died almost instantly.

As George Gardstein left the house he was tackled by Constable Walter Choat who grabbed him by the wrist and fought him for possession of his gun. Gardstein pulled the trigger repeatedly and the bullets entered his left leg. Choat, who was a big, muscular man, 6 feet 4 inches tall, managed to hold onto Gardstein. Other members of the gang rushed to his Gardstein's assistance and turned their guns on Choat and he was shot five more times. One of these bullets hit Gardstein in the back. The men pulled Choat from Gardstein and carried him from the scene of the crime.

Yakov Peters, Yourka Dubof, Peter Piaktow and Fritz Svaars, half dragged and half carried Gardstein along Cutler Street. Isaac Levy, a tobacconist, nearly collided with them. Peters and Dubof lifted their guns and pointed them at Levy's face and so he let them pass. For the next half-hour they were able to drag the badly wounded man through the East End back streets to 59 Grove Street. Nina Vassilleva and Max Smoller went to a doctor who they thought might help. He refused and threatened to tell the police.

They eventually persuaded Dr. John Scanlon, to treat Gardstein. He discovered that Gardstein had a bullet lodged in the front of the chest. Scanlon asked Gardstein what had happened. He claimed that he had been shot by accident by a friend. However, he refused to be taken to hospital and so Scanlon, after giving him some medicine to deaden the pain and receiving his fee of ten shillings, he left, promising to return later. Despite being nursed by Sara Trassjonsky, Gardstein died later that night.

Several witnesses had seen Nina Vassilleva with George Gardstein. Soon after the murders the police issued the following description: "Age 26 to 30; 5ft 4in; slim build, full breasts; complexion medium, face drawn; eyes blue; hair brown; dress, dark blue, three quarters jacket and skirt, white blouse, large black hat trimmed with silk." It was such a vague description that Isaac and Fanny Gordon, who rented a room to Nina, did not recognise her.

However, they did become concerned when they discovered that she had died her hair a "harsh, ugly black". Isaac Gordon also discovered her burning documents. According to Donald Rumbelow, the author of The Siege of Sidney Street (1973): "She told Isaac that she was the woman who had been living in Exchange Buildings and that she had heard that the police were going to carry out house-to-house searches; she did not want them to find these papers. Isaac pleaded with her to let him have them for safe keeping." Nina told Isaac: "It would have been better if they had shot me, instead of the man they have shot. He was the best friend I had... Without him I might just as well be dead." Nina agreed not to burn anymore documents and gave them to Isaac.

John Rosen went to visit Nina Vassilleva on the 18th December, 1910. She asked him "have you brought trouble". He gave a slight shrug and said "I don't know". Nina refused to let him in and he left the building. Ten minutes later Detective Inspector Wensley arrived. Issac Gordon had given Nina's documents to the police. After she denied knowing George Gardstein Wensley showed her the collection of photographs she had given Gordon that included one of her former lover.

Wensley did not arrest her straight away as he hoped she would lead them to the rest of the gang. Nina decided to flee to France but changed her plan when she discovered she was being followed. She told a friend: "If I go to Russia I shall be killed and if I stop here I shall be hanged." On 23rd December, detectives followed her to St Paul's Cathedral to watch the funeral of the three murdered policemen. They saw her purchase a small black-and-silver memorial card, with wood-block portraits of the three dead men.

Nina Vassilleva was arrested while walking along Sidney Street and she appeared in court on 14th February and was charged with conspiracy to commit a robbery. When the police searched her room they found the blue three-quarter-length coat she had been wearing on the night of the murders, and which still had large patches of dried blood on the front.

The trial of the Houndsditch murders opened at the Old Bailey on 1st May. Yakov Peters and Yourka Dubof were charged with murder. Peters, Dubof, Max Smoller, John Rosen and Karl Hoffman were charged with attempting to rob Henry Harris's jeweller's shop. Nina Vassilleva and Sara Trassjonsky were charged with harbouring a felon guilty of murder. Donald Rumbelow, the author of The Siege of Sidney Street (1973) has pointed out: "Nina Vassilleva looked pale as she stepped into the dock and moments later broke down and sobbed bitterly. Her tight-fitting black dress was shabby and a slouch hat of green tweed, with a feather, only emphasised her shabby appearance."

The opening speech of A. H. Bodkin lasted two and a quarter hours. He argued that George Gardstein killed Robert Bentley, Charles Tucker and Walter Choat and Smoller shot Gardstein by mistake. Justice William Grantham was unimpressed with the evidence presented and directed the jury to say that the two men, against whom there was no evidence of shooting, were not guilty of murder. Grantham added that he believed that the policeman were killed by George Gardstein, Fritz Svaars and William Sokolow. "There were three men firing shots and I think they are dead."

The prosecution's principal witness that linked Vassilleva, Peters and Dubof to Gardstein was Isaac Levy, who saw them drag him along Cutler Street. Levy came under a fierce attack from defence counsel. After his testimony, Justice Grantham said that if there was no other evidence of identification he could not allow any jury to find a verdict of guilty on Levy's uncorroborated statement. After Grantham's summing-up made it clear that none of the men should be convicted of breaking and entering, the jury found them all not guilty and they were set free.

Vassilleva was found guilty of conspiracy to commit a robbery but recommended that she should not be deported. Vassilleva was sentenced to two years' imprisonment, but five weeks later the Court of Appeal quashed her conviction on the ground of misdirection of the jury by Justice Grantham (he was himself to die a few months later).

Nina Vassilleva went back to cigarette-making and in the early sixties, when she was over seventy, was still living in a room by herself not far from the scene of the murders.