A special team traced the cellphone of the accused which led to his arrest.
A one-page hand-written suicide note was recovered from the spot where the officer was found unconscious and it is being sent to the hand-writing experts for examination.
The teenager was friends with a girl living in his neighbourhood and the girl's boyfriend did not approve of their friendship.
About 40 per cent of milk and milk product samples, which were seized during raids conducted by food safety officials in the last one month, were found to be of substandard quality, a senior official said on Thursday.
Punjab Minister Navjot Singh Sidhu on Thursday released CCTV footage that he said showed police action against peaceful protesters and subsequent firing leading to the death of two youths in Kotkapura in October 2015 following sacrilege incidents.
The Punjab government on Thursday withdrew in the "larger public interest" its notification for entrusting the CBI with the probe into the sacrilege cases reported in the state in 2015 and opted for a SIT probe instead.