British teenager Scarlett Keeling's mother Fiona Mackeown has written a letter to Prime Minister Narendra Modi requesting his intervention in the case of death of her daughter in Goa and has sought reinvestigation by setting up a SIT. "The local fishermen informed me (then that) she was murdered by a drug mafia in Goa, but as this drug mafia had strong connections with local police and politicians, it would be pointless for me to approach the criminal justice system," Fiona said in the letter to the PM, which she made public during a press conference today. Goa Children's court had last week acquitted two men who were charged with drugging and leaving Scarlett to die on Anjuna beach on February 18, 2008. "Upto now, I refused to believe that the local fishermen were right, and placed my trust in the system," the mother said seeking PM's intervention in the matter. She also said that she needs to know who 'killed' her daughter, if the two accused are not guilty. She demanded that the people responsible for the 'murder' of her daughter be identified and prosecuted. She said in the letter that after eight-and-half years of waiting and trusting the criminal justice system, she finds that the accused stand acquitted due to lack of evidence. "Those who destroyed the evidence were never charged. Those authorities, who shielded the criminals by providing them enough time to destroy the evidence were never charged," she alleged. Advocate Vikram Varma, representing Fiona, said they request the PM to intervene and set up a Special Investigation Team or an equivalent agency to reinvestigate the case. Scarlett was found dead on the famous Anjuna beach of Goa on February 18, 2008. Initially, Goa Police and later the CBI probed the case, which attracted international attention, besides raising questions on the safety of women in this world renowned tourist destination. Two men \u2013- Samson D'Souza and Placido Carvalho - were chargesheeted by CBI in the case. The duo were accused of leaving the girl to die on the beach after drugging and sexually abusing her. Last Friday, the court had acquitted them of all the charges leading to reactions of shock and disappointment from Scarlett's family and politicos in Goa. The Goa Children's Court had also raised serious doubts about the impartiality of the probe in the case.