A nineteen-year-old boy was on Tuesday arrested and his friend detained for their alleged role in the kidnapping and murder of a fellow student in Mumbai [Images], possibly due to ransom, the police said.

"We have arrested Amir Siddiqui Shaikh, who is responsible for the murder of Mukim Khan. We are still to ascertain his role in the crime. Sarfaraz, who also studies in the same college and a friend of Mukim, was detained on suspicion," Deputy Commissioner of Police Nisar Tamboli told PTI.

"Investigations into the case so far reveals that the money was the motive behind the crime. A phone call demanding Rs 20 lakh was made after Khan's kidnap," Tamboli said, adding that, "Khan, a class XII student of Rizvi College in suburban Bandra, went missing on February 13."

"Khan left home in the morning. Later that day, the victim's family received a ransom call demanding Rs 20 lakh. Initially, the family thought it was just a prank, as the call was made from Khan's phone," Tamboli said. But realising it was more than a prank call, the family members lodged a complaint with the Khar police, Tamboli said.

"Our team has questioned many of Khan's friends, including Amir. On Monday night, Khan's body was found in a decomposed condition in a gutter in Kalina," Tamboli said.

"We suspect the involvement of more than one person in this crime," said the DCP. Sources said Amir has confessed to the crime and took the police to the area where Khan's body was found.

In somewhat a similar case, Adnan Patrawala from Lokhandwala was killed on August 19, 2007, by three youngsters, who befriended him through the social networking site Orkut.

Sujith Nair, Ayush Bhat, and Khimmesh Ambavat, who confessed of killing Adnan by strangulating him, had demanded a ransom of Rs 2 crore from Adnan's parents. The trio panicked after the news of Adnan's abduction was aired on news channels and killed him, deserting his body in the marshes of Navi Mumbai.