G.R. No. 93201 , 93205, 93502. June 26, 1990.
SULTAN MOHAMAD ALI B. DIMAPORO and NURHUSSEIN UTUTALUM, petitioners, vs. COMMISSION ON ELECTIONS, ZACARIA CANDAO and BENJAMIN T. LOONG, respondents.

FACTS

Petitioners Dimaporo and Ututalum were candidates for Regional Governor and Vice-Governor, respectively, of the Autonomous Region in Muslim Mindanao in the February 17, 1990 election, opposing respondents Candao and Loong. During the canvass in Sulu, petitioners objected to the inclusion of election returns from 259 precincts across nine municipalities, claiming the returns were “spurious, obviously manufactured and/or statistically improbable.” The Provincial Board of Canvassers overruled the objections. Petitioners appealed to the COMELEC, which initially dismissed the appeals. The COMELEC En Banc later modified this, ordering the exclusion of returns from 88 precincts under the “Lagumbay doctrine” for being statistically improbable but including the rest.
Separately, in Tawi-Tawi, petitioners objected to returns from 36 precincts in Languyan municipality on identical grounds. The Provincial Board overruled them, but the COMELEC’s Second Division ordered the exclusion of 15 returns for being statistically improbable. Petitioners moved for reconsideration, seeking the exclusion of all 36 returns. The COMELEC En Banc denied this motion, prompting petitioners to elevate the case to the Supreme Court via certiorari.

ISSUE

Whether the COMELEC committed grave abuse of discretion in not excluding all the contested election returns from Sulu and Tawi-Tawi for being statistically improbable and obviously manufactured.

RULING

The Supreme Court dismissed the petitions, finding no grave abuse of discretion by the COMELEC. The Court upheld the COMELEC’s application of the Lagumbay v. COMELEC doctrine, which allows the exclusion of returns as “statistically improbable” only when they exhibit a unique, mathematically perfect uniformity—specifically, where all votes are cast for every candidate of one party and zero for all candidates of the opposing party. The COMELEC correctly excluded returns that precisely matched this pattern.
For returns showing variances from this perfect uniformity (e.g., 99% voter turnout, or a handful of votes for the opposing party), the COMELEC ruled they did not fall under Lagumbay and required evidence aliunde (external evidence) to prove fraud, which petitioners failed to present. The Court emphasized that the determination of whether a return is statistically improbable is a factual finding best left to the COMELEC, as the constitutional body endowed with expertise in election matters. The COMELEC’s decisions were based on a careful examination of the returns and the application of established jurisprudence. Its actions were neither arbitrary nor capricious but exercised within its legitimate discretion. Therefore, its resolutions were affirmed.