The presumption of regularity will never be stronger than the presumption of innocence in favor of the accused.

"The presumption of regularity in the performance of official duties in favor of the police officers will not save the prosecution's case, given the foregoing lapses and gaps in the chain of custody. The presumption stands only when no reason exists in the records by which to doubt the regularity of the performance of official duty. And even in that instance, the presumption of regularity will never be stronger than the presumption of innocence in favor of the accused. Otherwise, a mere rule of evidence will defeat the constitutionally enshrined right of an accused."

PRECEDENTS:
Link/Source: People of the Philippines v. Larry Mendoza y Estrada, G.R. No. 192432, June 23, 2014.

2017 Latest Application. READ Full Text.
[2017V416] PP vs Rommel Diputado