India, Aug. 20 -- A single word spoken during a phone conversation helped Telangana police crack the murder of a school principal who was allegedly stabbed 27 times by two Class 10 students in Nalgonda district.

The investigation into Roopa Reddy's murder uncovered resentment, a recce of her house and blood-stained currency that eventually led investigators to the two minors.

The murder took place on August 11. Nalgonda SP Sharath Chandra Pawar said police formed five teams and examined footage from nearly 70 CCTV cameras while searching for the killers.

The breakthrough came from Reddy's conversation with her aunt around the time of the murder. During the call, she addressed someone as "Babu", a term she commonly used for students at...