from january 2018, bitcoin price is always changing, a suddenly increased but after a second deep dropped will surly exist. it is the vise versa of bitcoin price last year (2017). until now the price of bitcoin from january upto now (june) is still dropping. so i was wondering if theres a group of people behind this bitcoin price drop?
Yes it could be. If you have many coins in your possession, you can make the market price up and down with your coin.
Manipulators want to make us panic buying or panic selling our coins, so they can buy with lower and sell with higher price in the market.