This moisture helps the quicklime to generate heat which begins to burn the body.
A couple of months later O'Connor came to Stafford House, where she was living, and he took her out to dinner. She told him that she had recently met Frederick George Manning, a guard on the Great Western Railway. Both men were smitten and both proposed to her over the course of the next few weeks. Maria just had to work out which had the most money. O'Connor seemed to be the richer, he spent freely, but he drank a great deal and she had no desire to saddle herself with an alcoholic. Manning currently only had his wages as a guard but told her that he expected to inherit a fortune from his mother. This was enough to convince Maria and the pair were married in St James' Church, Piccadilly, in May 1847.
Manning gave up his job on the railway and took a public house, the White Hart Inn, at Taunton. He was singularly inept as a publican and the pair soon had to sell up and move back to London. They moved into Miniver House, Bermondsey. Maria had discovered Manning's true situation by this time; there was no fortune to inherit.
She met up with O'Connor again and he was able to avail himself fully of her sexual favours. In fact he became a friend of both of the Mannings, occasionally visiting them for dinner. Maria realised that she had made a mistake in marrying Frederick. By now she had determined that O'Connor was a man of considerable wealth. Not only did he own a large amount of foreign railway stocks he was also a part-time money lender. Maria made up her mind, she must get her hands on the Irishman's fortune.
On July 23rd 1849 a bushel of lime was delivered to the house, which Maria paid for. On 8th August a large shovel was delivered. It was on that day that Maria sent a note to O'Connor asking him to come to dinner that evening. Her plans were, however, temporarily thwarted as he turned up with a friend named Walshe. Not to be frustrated in her purpose for long, she asked O'Connor to return the next evening and suggested that, if he came alone, there might be more on the menu than dinner.
The following evening O'Connor was seen crossing London Bridge by friends and the Manning's neighbours noticed the Irishman smoking a cigar by the back door. Maria told the man to wash his hands in preparation for dinner and led him into the kitchen, a lower-level room. O'Connor turned towards the basin and Maria placed a pistol behind his ear and shot him. Manning went into the kitchen only to find out that the man was not yet dead and was trying to speak. In Manning's own words, 'I never liked him, so I battered his head with a ripping chisel.' O'Connor's body was quickly covered in lime and assigned to a grave under the flagstones in the kitchen, where the pair then sat and ate their dinner.
The next morning Maria turned up at O'Connor's lodgings in Greenwood Street. His landlady let her into O'Connor's room and she rifled his belongings taking several hundred pounds in cash, gold watches and chains and a wad of foreign bonds. The next day, on another pretext, she returned to O'Connor's room and had another search for some more bonds that she felt ought to be there, but found nothing new.
On the 12th August two men came to the Manning's house. They said that they were customhouse officers and were concerned about the disappearance of their colleague. The Mannings admitted that O'Connor had dined with them on the 8th but said that they had not seen him since. This the two men found strange as they had already spoken to the friends who had seen O'Connor on London Bridge on the 9th when he had said that he was 'dining with Maria.' Maria insisted that they must be mistaken and asked the two men to let her know if they learnt of O'Connor's whereabouts.
Once they had gone Manning got into a panic telling his wife that the men were not customhouse officers but policemen. This threw Maria into a panic as well and they decided that they had to flee. Maria told her husband to go to a relative named Bainbridge and to sell the furniture for what it would fetch. As soon as he left Maria collected together everything of value that she could carry and left. Neighbours saw her leaving in a cab with three or four trunks tied to its roof. When Manning returned and found the house a shambles and his wife gone he realised that he was on his own. He grabbed a few items and went to Waterloo station where he caught the boat train for Jersey.
Police investigating the disappearance of the Irishman discovered that a woman matching Maria's description had ransacked O'Connor's room. They went to the Manning's house and, in the back kitchen, spotted that the mortar between two of the flagstones was still damp. They prised up the stones and soon found the body buried there. The word went out to apprehend the Mannings.
In answer to an appeal from Scotland Yard a cabman came forward and told of taking Maria to the South-Eastern Railway. There, using the name Mrs Smith, she had left two trunks. She had then been driven to King's Cross. At King's Cross Superintendent Haynes found two officials who remembered a woman who spoke English and French and seemed in a highly nervous state. She had taken the 6.15am train to Edinburgh. Haynes telegraphed Edinburgh police asking them to look out for the woman.
Maria was already in custody. She had tried to sell some of O'Connor's railway stock to a firm of brokers and had told them that her father was a Mr Robertson, a native Scot. This didn't fit with her thick French accent and aroused their suspicions. They had also already been warned that some railway stock had been stolen in London and that they should be cautious. Maria was returned to London where she was charged with murder and lodged in Horsemonger Lane Jail.
Frederick had another week's freedom before he was caught. Staying in St Helier he drew attention to himself by drinking prodigious amounts of brandy each day and, when he met a man that had known him in London, he fled to St Lawrence. The man who had spotted Manning read of the case in the papers when he returned to London and lost no time in telling the police. On August 21st Frederick was apprehended in his room and was returned to London.
Their trial opened at the Old Bailey on 25th October with each trying to blame the other for the killing. After a two day trial the jury took less than an hour to find both of the defendants guilty and they were sentenced to death. On 13th November 1847 they were hanged together on a gallows outside Horsemonger Lane Jail. Their end was watched by a crowd estimated to be between thirty thousand and fifty thousand people, the largest crowd ever assembled in Britain to watch a public execution.
Quicklime was used widely in prisons to speed up the process when disposing
of murderers that had been hung.