Theft in Train

After around six months of the incidence, We received a letter from the police stating that they were unable to find the belongings. Kindly advice, what can we do next? Can we put a case with the consumer forum? Case Detail: My mom and dad were traveling by Gour Express Train No.23154 in 2AC Coach Seat No.7 and Seat No. 32 and boarded in the train from Balurghat railway station at 5.00 p.m. on 23.12.2015. At about 09.00 p.m. my mom found that her handbag theft by someone which was near to her head on the berth in between Old Malda to Malda Town railway station. Due to this theft in the train we have lost valuable gold ornaments worth Rs7.5lakhs (Necklace-4nos, Gold Chain- 5nos., Mangalsutra-5nos, Gold Ring-7nos., Ear Rings-6pair, Bracelet-1No., Bangles-4nos.,Pala-2nos.,) and cash amounting Rs 15000/- , 2 mobile phones(+[deleted], +[deleted]), Pan Card, Voter ID Card, 2AC Train Ticket from Howrah to Kalyan Railway Station and Flight Tickets. Immediately informed regarding the theft to the Assistant Sub Inspector Shri.Chandan Sarkar who was present in the coach, subsequently he called the Travelling Ticket Examiner Mr.A.K.Roy and coach attendant Mr.D.K.Verma who were available in the train and reported and discussed about the theft and lost of the above things. Further according to their advice my dad have lodged a written complaint at the Sealdah Railway Station to the Incharge of Sealdah G.R.P.S. on 24.12.2015 at 7.00 a.m. once the Train reached at Sealdah railway station.