Vinu made withdrawals of big sums of cash for no reason.
Cyril for no apparent reason goes into a trance and is directed to exact spot of the bag of cash.
How can Christopher, a civilian or even a suspended officer (for the sake of the movie), act like a detective in front of a senior officer.
Eby thought he could win Jessy back by killing Vinu and went through all this trouble.
When they all go and check out the bag at the abandoned drain, the cash is missing. Nobody would have seen anything let alone see Cyril hiding the bag at that time in the night.
Shaan happened to be purchasing medicine when he ran into Vinu and that too when the former wasn't even sick.