Nigerians wey go vote for new president next month go get 18 contenders to choose from.

However, di three men wey pipo see as di leading candidates don chop separate accuse of trading in narcotics, money laundering and global tax avoidance.

None of dem no ever dey indicted, wey fit stop dem from running for office, but di high-profile allegations don raise questions over dia candidacy.

"Na choosing between bad candidates," Auwal Rafsanjani, wey be head of di Nigerian branch of anti-corruption watchdog Transparency International tok as e point out how widespread corruption don cause disturbing levels of underdevelopment and poverty for di oil-rich nation.

Di three top contenders na Bola Tinubu from di governing All Progressives Congress, Atiku Abubakar from di People's Democratic Party and Peter Obi from di Labour Party.

Di three of dem tok say dem make dia money legally and don deny any wrongdoing.

Bola Tinubu files

Oga Tinubu, wey serve as two term govnor of Nigeria richest state Lagos na probably di most talked-about candidate on di ballot.

Plenty debates about im age, name, health status, work profile plus di authenticity of im university certificate dey ground, but na how e take make im money – di source of im wealth na im pipo dey question most.

Many pipo believe say 70-year old Tinubu na one of Nigeria wealthiest politicians, although official records no dey.

Di most visible extent of im wealth na one mansion wey dey for Ikoyi area of Lagos – highbrow area of Nigeria commercial hub. Na on election day for 2019, onlookers witness di rare sight of two armoured vehicles, wey dey similar to bullion vans wey banks dey use transport cash, dey drive enta im gates. Im aides don deny di subsequent accuse say e get hand for vote-buying.

But dem don raise questions about im wealth. For December, e tell BBC say im inherit some real estate wey im invest inside, but for di past, e bin tok say im become  "instant millionaire" wen e dey work as auditor for Deloitte and Touche.

He say im bin save $1.8m (£1.5m) from im wages and oda allowances, wey be nearly di same amount wey dem see for accounts wey dey linked to one 1993 disagreement wit authorities for US.

For documents wey dey publicly available, di US Department of Justice allege say from early 1988, accounts wey dey opened in di name of Bola Tinubu hold proceeds from sales of white heroin, one banned substance.

Kevin Moss, di special agent wey investigate di operation, allege say Mr Tinubu bin work for dia prime suspect Adegoboyega Akande.

Di agent say Mr Tinubu bin initially confess to am on top phone say e know Mr Akande, but later withdraw im statement say im no get any financial transactions wit am.

While di court confam say e get cause to believe di money for di bank accounts na proceeds of drug trafficking, Mr Tinubu and di odas deny di allegations, and di court never make final order on top di origin of di money.

Instead, oga Tinubu, wey dem no personally charge on top di money, reach compromise settlement wit di authorities and forfeit $460,000.

Oga Tinubu don always deny any links to di drugs trade and im spokesman, Festus Keyamo, say di forfeited funds na part of a civil forfeiture and no be criminal one.

Last year, he also do out-of-court settlement wit one accountant Oladapo Apara, wey get fall out wit Tinubu.

Mr Apara na di founder of Alpha Beta Consulting, wey dey established wen Mr Tinubu be govnor and e receive well-paid contract to track taxes for Lagos state, wey e still hold.

Di accountant allege say oga Tinubu get 70% controlling interest for di company through proxies - and di firm dey receive about 10% commission on revenues collected, wey e estimate to be $3.48bn between 2002 and 2018.

Tinubu deny am say e no dey receive commissions on taxes wey di Lagos State goment dey collect.

Mr Apara say dem sack am from di firm for 2010 afta e allege say magomago don enta di funds – and e begin long legal battle to seek redress.

He argue say dem no fit sack am as a founder of of di firm and demand for compensation from Mr Tinubu, wey lead to court case for 2021.

For September 2018, e also tweet say im don write to Nigeria financial-crimes regulator, as e accuse of Alpha Beta of tax evasion – di actual letter wey follow di tweet, wey give full details of di allegations, don dey deleted from im account.

Alpha Beta deny di allegations, e say dem sack Mr Apara sake of fraud, wey e don deny.

Mr Tinubu don consistently deny links to di firm, but e be party to one undisclosed settlement between Alpha-Beta and Mr Apara last June, wey lead to di termination of di parties' claims against each oda.

BBC bin ask Tinubu about di settlement, di US allegations plus questions on top im wealth but e no reply di request for comment.

Atiku Abubakar and di US Senate

Oga Abubakar dey carry imself as di most experienced candidate on di ballot, as e bin don serve as vice-president between 1999 and 2007 - and na for dis period, some controversy dey.

Im former boss, ex-President Olusegun Obasanjo, bin accuse am of embezzling $145m from di Petroleum Technology Development Fund (PTDF) for 2003.

Obasanjo, wey no dey shame to share im opinions about oda politicians for public bin dedicate one chapter for im book My Watch, wey e publish for 2014, to di alleged transgressions of im former deputy.

Mr Abubakar deny di accusations, e say dem put di $145m for commercial banks to gain interest so dem go fit put am back for PTDF projects.

Di 76-year-old say im first make money from farming and from di houses e get for im home state of Adamawa. E be former customs officer, e say im recognise early in life say im get "a good nose for money".

Na for di 1980s e establish one oil-servicing firm wey catapult am enta di world of di wealthy.

Opponents don accuse am of flouting one law wey ban civil servants from engaging in private business other dan farming.

Mr Abubakar spokesperson describe im venture as a small business wey many public servants dey do, like to dey use dia car as a taxi or setting up a shop in front of dia house to support dia families.

"He only invest im income to earn interest. E bin no dey do any oda work in form of private work like wetin you dey reason," Paul Ibe tell BBC.

For 2010, one US Senate committee report allege say between 2000 and 2008, Mr Abubakar, through one of im four wives, transfer more dan $40m in "suspect funds" into di US from offshore shell companies.

Di report claim say at least $1.7m of dis come from bribes wey German technology company Siemens pay, wey plead guilty to bribery charges for 2008 and agree to pay a $1.6bn fine.

E also be major figure for di corruption trial of former US Congressman William Jefferson, wey for di Senate report describe Mr Abubakar as "really corrupt" and say e need money to bribe am to approve US company business deals for Nigeria.

Dem convict Mr Jefferson for 2009 and dem sentence am to 13 years in prison, wey dem later reduce.

"Atiku Abubakar no dey on trial for corruption or any oda misconduct either for Nigeria or any foreign land," Mr Ibe tok.

"E fit only udeynfit for public office wen e dey indicted by court of law. Dat no be di situation." 

Peter Obi and di Pandora Papers

Peter Obi, wey don also serve two terms as govnor – for im case for di eastern Anambra state, no dey hide im ogbonge wealth, wey e say im make through banking and importing various goods into Nigeria.

"Mr Clean" as im supporters dey call am sake of say e dey rare to see Nigerian politician wey no get accuse of embezzling public funds, e come as surprise to many wen im name come up for 2021 for di Pandora Papers. Dis na leak of almost 12 million documents wey reveal di hidden wealth, tax avoidance and, in some cases, allegations of money laundering by some of di world rich and powerful.

Nigeria Premium Times, one of di newspapers wey work on di Pandora Papers investigation, allege say di documents show say for 2010, wen Mr Obi be Anambra govnor, e set up one company, wey e name afta im daughter, for di British Virgin Islands to help am avoid tax.

To make use of tax haven no dey illegal, though setting up foreign bank accounts wen pesin dey serve as public officer no dey allowed.

Di Premium Times say dis show wen Mr Obi bin fail to declare im assets, and e also allege say e bin fail to resign from di UK-registered company Next International, of which e be director wen e become govnor – and dey engage for private business, wey no dey allowed for public officers. Im resignation dey registered 14 months into im term.

Dem no ever charge di 61-year-old over any of di revelations.

Mr Obi tell BBC say one impeachment trial don investigate di allegations wey surround im business affairs for 2006 and see say e act within di law.

E add say im bin establish one blind trust to oversee im business arrangements, wey include di family offshore holdings. "A blind trust dey allowed within di law," e tok.

Mr Obi don also dey accused of one conflict of interest afta e invest $20m of state funds wen e be govnor for inside one brewery, wey im family get shares through Next.

E deny di allegations, say di investment greatly benefit Anambra over di years.

Criticism also dey ground say Anambra invest for Fidelity Bank, wia e once be chairman.

"Anambra state bin invest for Fidelity Bank, wia I get interests, because na public quoted company," e tell BBC, and dismiss any suggestion say any of di revelations about im finances cast doubt about im fitness for office.

President Buhari legacy

Recently, one corruption row bin blow up between Mr Abubakar and Mr Tinubu camps.

Each camp dey accuse di oda candidate of siphoning public funds through proxy companies wey dey known as special purpose vehicles (SPVs) wen dem dey office, say dis one make dem ineligible to run, and di campaign spokesman from Mr Tinubu APC say im don carry di case go court.

Both deny di allegations, but di issue now dey dominate di rallies.

But di general issue about addressing corruption no be di major talking point for dis electoral campaign.

Dis na in contrast to di frenzied anti-corruption promises wey see President Muhammadu Buhari election for 2015.

Di 80-year-old go step down dis year, but analysts argue say im no do enough to tackle di problem wen e dey office.

"Maybe Nigerians dey too familiar wit corruption and don notice say notin fundamental dey change," Mr Rafsanjani tok.