Checking claim of rigging of Peter Obi and Atiku during Nigeria presidential election

Dem don declare Bola Ahmed Tinubu as di winner of Nigeria fiercely contested presidential election but many pipo, including opposition parties, don claim say dem rig di election.

Dem don ask make dem cancel di election as dem allege breaches of di Electoral Act and possible collusion by di Independent National Electoral Commission (Inec) to doctor di result favour of Oga Tinubu.

Inec don deny di allegation and also Oga Tinubu party, di ruling All Progressives Congress (APC).

As for di opposition parties, so far dem neva offer any concrete proof to back up dia allegations.

But di Labour Party, wey dia presidential candidate Peter Obi come third, don tok say dem go go court to overturn Oga Tinubu victory. E neva clear which evidence dem present.

For di heart of di dispute na di newly introduced electronic voting system, wey dem sabi as Bvas, wey suppose make di manipulation of results more difficult and di polls dey more transparent.

Di widespread inability of electoral staff to upload results from polling units to Inec server help fuel allegations of one conspiracy.

Fears of rigging bin emerge for di morning of di election wen one popular influencer alleged on social media say hackers bin breach Inec IReV portal, wia dem wan upload results. Dis post bin get ova 1.4 million views on Twitter.

Di BBC investigate di claim and find out say di site wey dem reference na one phishing site wey dey masquerade as di Inec website. Inec itself bin give assurance say im site dey "well-secured", and dem no fit tamper wit am.

Later, as delay to upload results to di server kontinu, four opposition parties, including di People’s Democratic Party (PDP) and Labour, accuse Inec say e dey violate di Electoral Act as e fail to transmit result to di IReV portal.

Inec regulations and guidelines, require make dem scan and upload results to di server from each of di more dan 175,000 polling stations afta party agents and election officials sign am.

As e complain about di failure to upload results, PDP vice-presidential candidate Ifeanyi Okowa, for one joint press conference wit im Labour counterpart, Yusuf Datti Baba-Ahmed, allege say either Inec bin "connive [wit di ruling party] or dia system dey down".

"If di system dey down and dem sabi say e dey down, den dem suppose don postpone di election. If di system no dey down, and dem no allow di upload of di results, [e] mean say dem don connive, and dem no longer dey neutral and impartial," Dr Okowa tok.

Inec apologise for wetin dem call "technical glitches", and say dem go investigate any discrepancies between results on di portal and dem go investigate and resolve "physical results".

Inec also blame delays on factors wey dey beyond im control, like di lack of internet access for some polling stations.

Staff den gatz take di Biomodal Voter Accreditation System (Bvas), wey dem use to accredit voters and upload results, to Inec offices to do am, dem tok.

E also get reports of voters wey dey allow election officials to use hot-spots on dia mobile phones to access di internet and so access di system.

But many pipo complain say di results of di presidential election dey slower to upload dan results from di parliamentary election dem hold at di same time. Inec neva offer explanation for am.

For oda concerns wey di opposition raise, di PDP's Dino Melaye, wey lead to a walkout of some opposition party representatives from di results collation centre, allege say over voting dey for Ekiti - di first state to announce results, and wey back Oga Tinubu.

To dismiss di allegation, Inec chairman Mahmood Yakubu say di total number of vote cast for Ekiti, one stronghold of Oga Tinubu for south-western Nigeria, dey less than di total number of accredited voters.

On claims on social media say dem publish di results from Ekiti five days before di elections, di Inec chairman say dat kain stories fit only pass for "fake news".

E also get videos on social media wey show voter intimidation and ballot-snatching, and violence for some polling stations, especially for di biggest state, Lagos – wey Oga Obi win in a blow to Oga Tinubu - and Rivers state, wey e win.

Di BBC don confam di authenticity of some of dis videos and BBC journalists arrive for one polling unit for Lagos just as thugs scata di voting process.

Plenti fotos of ballots, wey dem say e show evidence of ballot-tampering, also dey circulate on social media.

Di BBC bin check some of di fotos and trace dem back to uploads on Inec server.

Di BBC notice extensive alterations on some of di results wey dem upload, but no fit confam if dem don alter dem maliciously.

E also get instances wia, instead of uploading foto of presidential election result to di Inec website, e appear like dem post mugshots of pipo.

Di BBC investigate two cases wey we highlight on social media.

For one foto dem share widely, someone navigate di Inec portal to review results from Ado-Ekiti, di capital of Ekiti state.

One foto of di presidential election results from dat ward suppose dey dia wit di signatures of party agents. Instead na foto of one woman show for di screen.

E no dey clear how widespread such errors be, and weda dem be di result of lack of training or deliberate manipulation, but e go pile pressure on Inec.

Di BBC also notice a mix-up of presidential election results from some of Nigeria 36 states. For instance, dem upload plenti results from Sokoto for di north to wia dem suppose upload results from polling units from Rivers for di south.

Oga Abubakar win Sokoto while Oga Tinubu win Rivers, wey dem bin dey expect to back Peter Obi.

Dis wrong uploads, di BBC see say e, affect results for many states. But subsequent checks show say many of di affected polling units now get di right results.

Online, ruling party supporters dey point to losses wey Oga Tinubu suffer - including for di capital Abuja and di biggest city, Lagos - as proof say di election dey free and fair.

Oga Tinubu imself acknowledge say e get lapses for di election but say dem "dey relatively few in number and e dey immaterial to affect di outcome".

However, many young pipo wey back Oga Obi for di vote don dismiss di whole tin as a "sham".

Di election na di most tightly contested since military rule end for 1999 - and not surprisingly di result don prove to dey deeply polarising.