A Mumbai session's court on Monday acquitted the four men arrested for the 2007 murder of teenager Adnan Patrawala.
A fifth accused was a minor at the time of the murder and was tried separately by the Juvenile Justice Board.
Friend turned foe: Adnan (left) with Ayush Bhat, one of the accused who kidnapped him for a ransom of Rs 2 crore and later killed him
Sujit Nair, Ayush Bhat, Rajeev Dharaiya and Amit Kausha were acquitted of charges of extortion, kidnapping and murder; as the court felt that evidence collected by Mumbai Police was weak.
The fifth person was not named as he was a minor at the time of the murder.
Adnan, who was 16, was discovered dead in the bushes of Navi Mumbai, in August 2007. He had been strangled. His father's car was found on Palm Beach Road at Vashi. He had left his home to meet with friends at a gaming centre.
His five alleged killers included two teens. They had befriended him at a gaming parlour at a mall in North West Mumbai. They interacted with him regularly on Orkut.
The police claimed that the accused wanted quick money as they had to settle some outstanding debts. It said that the accused drew up a list of people they could kidnap for ransom.
To them, Adnan appeared gullible and came from a wealthy family, as his father was a businessman in Andheri.
On August 18, 2007, Adnan took his father's Skoda to meet his friends at the Inorbit Mall in Malad. The group of five men asked Adnan to drive with them to Kandivli. They allegedly spiked a drink that he had. The next morning, Adnan's father received a call asking for Rupees two crore as ransom.
Meanwhile, news of the kidnapping broke on TV. So, Adnan's abductors strangled him and dumped his body before taking local trains home.
Key evidence submitted in the case included exchanges between Adnan and his alleged killers on social networking site Orkut. One of those accused of his murder allegedly told the police where Adnan's blood-stained clothes were hidden. The police relied heavily on circumstantial evidence. One of the prosecution witnesses claimed to have seen the accused helping Adnan into the car in a drowsy condition.
Photos: Aamir Khan with brother Faisal, ex-wife Reena Dutta at MAMI
Photos: Sonakshi Sinha, Sushant Singh Rajput at Mumbai airport
Spotted: Ajay Devgn and Kajol at an event in Mumbai
Birthday special: 21 cricketers who made their Test debut as teenagers
Pics: Prabhas, Tamannaah Bhatia at 'Baahubali 2' first look launch at MAMI