While the 16-year-old boy died, the girl was hospitalised with a deep gash on her neck, they said.
SP, City, Akash Tomar said that a 16-year-old boy was returning after a stroll with a girl, student of class X, on Tuesday evening.
Some unknown person stabbed Rahul to death and slit the throat of the girl, Tomar said.
The girl was admitted to a nearby hospital where she is undergoing treatment, he added. The body of the boy has been sent for post-mortem, the SP said.
The girl presently is not in a position to give any statement, Tomar added.