It was about 2 am in the morning of April 1, 1868. The beat constable after completing his round was returning to Amherst Street when he noticed a bundle of female clothes lying on the other pavement.  In the light of his bull’s-eye lantern he realized it was a body of a young woman lying in a pool of blood. The throat was slit open diagonally. The weapon used to commit the crime - a long sailor’s knife, “moderately sharp”, was found near the spot. 

The constable had crossed the spot only an hour ago and did not notice anything unusual. Leaving behind another constable to guard the body, the beat constable rushed to inform the inspector about the murder. It was evident from the ring in her right hand that the deceased was a Christian and a married woman. The body was kept at the mortuary of Calcutta Medical College. However, despite the efforts made by the police, no one came forward to identify the body. As the body showed signs of decay, the police decided to dispose it. Messrs Sache and Westfield photographed the dead body before it was buried. 

Meanwhile, the police surgeon was in a dilemma, whether it was a case of suicide or homicide. Since there was no sign of struggle, suicide could not be ruled out. Finally, it was concluded that the wound would not be so low if it was a self-inflicted one, hence it was a case of homicide. The police was not sitting idle either. Copies of the photograph were circulated in and around the city including the suburbs and finally, a man called Harris, a resident of 100 Baithakhana Lane came forward to identify her. The deceased woman was identified as Rose Brown, his tenant, residing in one of his godowns in the same compound. The local beat constable then informed police that she was frequently seen with Madhub Chander Dutt (described as a "bad character" by the police). Meanwhile, a search of her belongings revealed a photograph of her paramour, Kingsley, who also did not enjoy much of a reputation in police circles. 

Rose Brown had left his quarters in Howrah some months ago and first took refuge at a house in Zigzag Lane but shifted again, apparently because she was scared that Kingsley would discover her there. She apprehended that he would kill her for deserting him. Police arrested Madhub Dutt who owned a shop in Boubazar and sold cutlery and knives, mostly procured from sailors. It may be mentioned here that Rose Brown possessed gold ornaments worth some Rs 600-Rs 700 which were never found. A search at Kingsley’s quarters revealed a shirt, the sleeves of which were still wet, some clothes belonging to a female with blood stains on them and finally a key which fitted into the lock found in Rose Brown’s quarters.  

The sensational murder in the middle of a key thoroughfare and failure of the police to nab the culprit raised a storm. Public reaction was strong and Lalbazar reeled under pressure. In those days Sir Stuart Saunders Hogg, after whom New Market was named, acted as both the police commissioner and chairman of the Municipal Corporation. The massive public reaction over the unsolved murder case that came to be known as the Amherst Street Murder can be gauged from the report that appeared in July, 1868. It read: “ Government has sanctioned a reward of Rs 1000 to any who shall adduce evidence leading to the conviction of the murderer of the woman Rose Brown on the 31st March (actually, 1 April). There seems no probability that the police will succeed in finding out the murderer in this case any more than the Ezra Street murderer.”

 In fact, in the same year 5 other women were murdered, among them 3 were sex workers and one was an old woman. Under tremendous pressure Sir Stuart Hogg, the then police commissioner decided to set up a detective department in Calcutta Police with A Younan as the superintendent and R Lamb as the first inspector in November 1868. The subordinate staff consisted of four darogas, ten head constables and equal number of second grade constables and third grade constables. 

 Meanwhile, the case of Rose Brown was being investigated by Richard Reid, an ace police detective who later on became the superintendent of the unit in 1873. He was also appointed as the bodyguard of Prince of Wales (later Edward VII) when he visited Calcutta in 1875-76. Reid noted down the case details in his book - Everyman his own detective. However, he refrained from mentioning the name of the murderer – perhaps in the absence of conclusive evidence against either of the two prime suspects. 

Reid’s book provides not only an exciting reading into the crimes committed in 19th century Calcutta but also how, observation and deduction helped detectives to crack the mysteries at a time when criminology was still at a nascent stage. He also wrote about certain chilling practices in native society such as cold sati where young widows involved in illicit relationship were forced to consume poison to avoid a scandal. They often died during illegal abortions or even if they survived the new born babies were killed by putting ashes in their mouths. Reid termed these as undetected crimes in which everybody, including the district collector preferred to look the other way.  

  After Hogg’s departure, his successor, S Wauchope submitted in his administrative report that the system had not turned to be an effective one. According to the police commissioner: “ The local inspectors finding that the detective department was taking all the credit in special cases lost interest and became careless and indifferent about crime, and lost all knowledge about "bad characters" in their divisions. While the detective department being practically of little use without local knowledge or assistance, worked often in the dark, with unfavourable or dubious results.” Though he abolished the force, the detectives directly reported to him.  Hoggs was not fond of employing natives in force but educated Bengalis who did not show much enthusiasm in regular policing turned out to be exemplary detectives. Kalinath Bose and Sreenath Pal earned quite a name for their investigating skills. Bose even got a reward of Rs 2000 from the Maharajah of Travancore in 1875 for successfully investigating the robbery of crown jewels, retrieving the loot and arresting the culprits.

 The murder of Rose Brown also turned out to be a milestone in the field of medical jurisprudence. Photography came to be used throughout the country to identify bodies before they got disfigured due to rapid decay and to record “every detail of a scene of bloodshed as it appeared when it was first disclosed to police in a place perhaps 60 miles from sadar station” where despite every attempt made by the police surgeon and civil magistrate, it would be impossible to reach on time. In Rose Brown case a small pointed supernumerary tooth, between the middle incisors of her upper jaw helped in the identification of the hapless victim through the use of photography.