They killed him when their ransom demands were not met. This is all according to Islamic law. Here is a salient passage on this issue from a Shafi’i manual of Islamic law:
When an adult male is taken captive, the caliph considers the interests … (of Islam and the Muslims) and decides between the prisoner’s death, slavery, release without paying anything, or ransoming himself in exchange for money or for a Muslim captive held by the enemy. (Reliance of the Traveller o9.14)
A revered Islamic jurist, Al-Mawardi, agrees with Reliance of the Traveller:
As for the captives, the amir has the choice of taking the most beneficial action of four possibilities: the first, to put them to death by cutting their necks; the second, to enslave them and apply the laws of slavery regarding their sale or manumission; the third, to ransom them in exchange for goods or prisoners; and fourth, to show favor to them and pardon them. (Al-Ahkam As-Sultaniyyah (The Laws of Islamic Governance), 4.5)
“My son was lynched by his Muslim friends: Mother of 14-year-old cries for justice,” by Priyanka Sharma, Mail Today, July 16, 2017:
A mysterious case of the murder of a 14-year-old boy has surfaced in the national Capital, with his mother alleging that he was held hostage and lynched by some Muslim friends.
The victim, identified as Yogesh Kumar, was found dead under mysterious circumstances near New Delhi Railway Station last month. Multiple injury marks were found all over his face and the body indicated that he was battered to death, doctors said. However, police remain tight-lipped over the cause of death considering it a communally sensitive matter.
Yogesh (14) was found in a pool of blood near the New Delhi Railway Station with blunt injuries on his face, back and neck.
Yogesh’s body was brought to the Lady Hardinge Medical College (LHMC) by police for the postmortem examination on June 23. Doctors who conducted autopsy said the injuries on his body were clear signs of his being attacked with a sharp object. Victim’s mother, Seema alleged it was case of lynching by his Muslim friends, who had demanded money from her while keeping Yogesh hostage. She even claimed that they made her hear Yogesh’s voice for once who was trembling with fear.
HIS MUSLIMS FRIENDS LYNCHED HIM
Recalling the horrifying incident to Mail Today, she said, “On June 23, Yogesh left home after he got a call from his friend Arif. He, along with other friends, including a girl Fatima, first kidnapped my son, later demanding Rs 10,000 from me. I was told that if money was not given on time, they will kill my son.” “The very next morning, I was told that my son was killed and thrown somewhere along the railway track near New Delhi station,” Seema said. Yogesh’s family lives in Shahadra’s Meet Nagar. Despite being very young, he had been working to fetch money for his mother’s treatment….