Suraj, a student of class X was involved with a girl of his school and had eloped with her on Friday, police said.
According to the police, two of Suraj's friends promised to provide a safe haven and took them to a hilly area in Amber near the highway on Friday night.
Later, both the accused snatched valuables from them and misbehaved with the girl, Police Commissioner B L Soni said.
When Suraj protested, Himmat and the other minor accused stabbed him, leaving him dead, the officer said.
After the murder, Himmat allegedly raped the girl and attempted to kill her also, but the other accused prevented him from this, Soni said.
The girl went back to her home and narrated the incident to her family, the police officer said.
"Police recovered the body and knife yesterday in hills near Kukas area while the accused were held today," Additional Commissioner Girraj Meena said.