mystery

"Ria how much more time you need to get ready, we r getting late" rohit said firmly.
Rohit n ria were madly in love n were famous as lovebirds in college.
They are going to attend house warming party thrown by their college  friends nisha n raghav.
Scene 2: both in car rohit on driving seat n ria besides him.
Rohit in his mind" today i ll get rid of you ria, sorry". Ria in her head "sorry rohit".
Scene 3: in party all the college friends present (nisha n raghav d couplr,nakul,pranav,niharika and anuj).
After greetings nisha takes ria along with her to meet others ,nakul joins them, drinks arrived they took the glasses n apart.
Pranav goes out for smoking, niharika standing at the window watching him. Niharika changed her sight for few seconds n when look back pranav is not there, she moves out to look for him.
Suddenly anuj started shouting on raghav, everybody intervene and make them calm after that anuj left the party.
Nisha went into the kitchen to bring the glass of water, suddenly she sees a shadow in her garden she moves towards that.
After few minutes ria n rohit told raghav" there is some urgency we have to go, where is nisha"
Raghav "she must b inside i ll call her"
No no we r getting late u inform her.
Nisha is still missing, raghav moves towards their backyard to look n he finds her body lying there.
Police arrived n found bodies of nisha , nakul, pranav n niharika.
Nisha was stabbed by a knife, nakul has poisoned, pranav n niharika were hit with hammer kind of thing.
Later police found rohit's car on high way .
Flash back
2008, rohit n ria sitting on bench anuj came. Anuj n ria are cousins, he is their junior. Anuj n nisha are in same batch they are best frnds,people around have doubts that they r dating but the fact is nisha likes someone else from senior batch.
Raghav is the most sincere person of the college, pranav has the playboy image n nakul the chipku. Niharika the sweetest girl having the caring heart.
2015, party at raghav's place.
A tray with 3 glasses of juice, hand appear n add something to the glasses.
Nakul had the drink, the other two left the drink untouched as they got busy in talking.
The drinks were served for ria, rohit n nisha.
(Was ria aware of poison or rohit)
Rohit is a chain smoker n anuj too had developed the habit of smoking but hardly anyone knows about it. Pranav is going through toughest time of his life, he moves out of party to spend some time alone. Niharika is worried for him.
Rohit n ria are snatching a glimpse of each other as if they have something to say to other.
Ria n anuj's relations aren't smooth these days, they are having property issue.
When anuj approaches her she left, went inside kitchen rohit is watching all this.
After fight with raghav anuj left the party. Ria received a call from anuj den she n rohit left the party.

Part 3 (i)
Police found rohit's car but nobody was there and from first investigation there were no traces of snatching n other mishap found.
But the police got some pieces of divorce paper in the car.
When police called rohit he said they are safe and at farmhouse with anuj n sandhya.
Rohit describes the whole story.
As me n ria were dealing with some issues, actually a misunderstanding. I was planned to take a divorce. when anuj called he wants to meet us at highway.
When we were waiting for him, ria presented me the sorry card and described what she had been through n we realized our mistake after that i tear the divorce papers.
Anuj introduced us with sandhya his gf n we planned to go to the farmhouse for celebration as we were moving had a flat tire so left the car there.
Anuj told police that, raghav is having a suspicion on him n nisha, he feels they are in a relationship, which is not right.
Raghav's confession
I wanted to kill anuj n nisha, i added poison but nakul died, when he started feeling uneasy i took him to kitchen when poison killed him i hid his body in kitchen. I knw anuj smokes whenever he gets tense, i try to make nisha tense which ultimately tensed anuj... I was waiting outside but i hit pranav by mistake of anuj and niharika had seen everything so i had to kill her...
Den anuj had fight with me i feel it is the best time i kill nisha n anuj will b the suspect... I said i need to wash my face n went into the room n from behind door went to the garden n den into d kitchen. .. Before nisha could recognize me i stabbed her.