The following links must be established in the chain of custody in a buy-bust situation:
FIRST, the seizure and marking, if practicable, of the illegal drug recovered from the accused by the apprehending officer;
SECOND, the turn over of the illegal drug seized by the apprehending officer to the investigating officer (within 24 hours);
THIRD, the turn over by the investigating officer of the illegal drug to the forensic chemist for laboratory examination; and
FOURTH, the turn over and submission of the marked illegal drugs seized from the forensic chemist to the court.
People vs. Constantino, Jr. GR No. 199689, March 12, 2014