There is no evidence that the diploma Nigeria's President Bola Ahmed Tinubu submitted to the country's electoral commission was forged, the BBC's Global Disinformation Team has found.
Allegations that President Tinubu's certificates were faked went viral on social media following the release by Chicago State University (CSU) of his academic records last week.
We have looked at some of the most widely circulated claims.
The release of the president's academic documents is the culmination of a judicial case filed in August by one of his main rivals in February's presidential election, Atiku Abubakar of the Peoples Democratic Party (PDP).
Mr Abubakar was hoping to have the victor disqualified after accusing him of falsifying the CSU diploma of Bachelor of Science in Business Administration awarded in 1979 that he submitted to the electoral authority (Inec).
To obtain evidence for his case in Nigeria, Mr Abubakar approached a US court in August, requesting it to compel CSU to release Mr Tinubu's academic records through a process called discovery, where the parties exchange information including documents ahead of a trial.
Mr Tinubu's lawyers opposed the discovery application, citing privacy concerns, but the US court decided it should proceed.
The documents requested by Mr Abubakar were:
A copy of any diploma issued by CSU in 1979
A copy of the diploma CSU gave to Mr Tinubu in 1979
Copies of diplomas with the same font, seal, signatures, and wording awarded to other students that are similar to what CSU awarded to Mr Tinubu in 1979
Documents from CSU that were certified by Jamar Orr, who was then a staff member of CSU, in the 12 months from 1 August 2022
In response to request one, CSU submitted seven diplomas covering different disciplines with the names of the students redacted. According to the university's registrar, these diplomas had not been collected by the students.
In response to request two, CSU stated that it could not find the diploma they issued to Mr Tinubu in 1979, because they do not keep copies of diplomas already collected by students.
In response to request three, CSU stated that it produced for Mr Tinubu a replacement diploma dated 27 June 1979. It also released diplomas awarded to other students that bore similar font, seal, signatures and wordings as Mr Tinubu's diplomas.
In response to request four, CSU submitted other academic documents initially attested to and released by Mr Orr.
In line with the judge's ruling, Mr Abubakar's lawyer Angela Liu last week questioned Caleb Westberg, CSU's current registrar, in a deposition.
The BBC was given access to the deposition transcript by Mr Abubakar's spokesperson, Phrank Shaibu.
Some social media users in Nigeria allege that the deposition and the diplomas released by CSU confirm that the diploma submitted to Inec by Mr Tinubu was forged. This claim was also repeated by one of Mr Abubakar's lawyers, Kalu Kalu, at a press conference last week.
We found there was no evidence to support this claim.
The CSU released several diplomas issued between 1979 and 2003. We analysed all of them.
There are three different diplomas for Mr Tinubu that we refer to throughout our analysis:
The original one, from 1979, which he has said in the past was lost when he went into exile in the 1990s
The second one, that he submitted to Inec - supposedly a replacement diploma from CSU (it is similar to diplomas issued by CSU in the 1990s)
Additionally, CSU holds another replacement diploma for Mr Tinubu that they say is probably from the early 2000s that he never collected
The allegations on social media are based on a comparison between the document Mr Tinubu submitted to Inec and the 1979 diplomas released by CSU.
During Mr Westberg's deposition, Mr Atiku's lawyer focused on the copy of the diploma President Tinubu handed to the electoral commission and suggested that it was unlike any of the diplomas released by CSU.
However, while Mr Westberg agreed with Ms Liu that the diploma in question does not look like the samples from 1979, he stated that the certificate actually looks like three of the diplomas CSU released to Mr Abubakar. Our analysis confirms this.
It turns out that the discrepancy in the appearance of the diploma is down to it having been re-issued in the 1990s.
Mr Westberg said the template of CSU's diploma has changed several times over the years. He said any request for a new diploma would resemble the current template at that time, no matter when the student graduated.
As such, if Mr Tinubu had reordered his diploma in the late 1990s, what he would have been given would look like what was obtainable then.
Three of the diplomas dating from the 1990s that CSU submitted were similar to Mr Tinubu's.
One of them, which bears the date 18 December 1998, is identical (aside from the names, class of degree, and dates) to the diploma Mr Tinubu handed over to Inec.
Mr Westberg also stated that CSU does not keep notes of when a graduate asks for the reissuing of a diploma and therefore Mr Tinubu's request for a copy of the diploma was not recorded.
The copy he gave to the election commission had part of the university logo missing, which Mr Westberg said in his deposition was possibly "cut off" when it was photocopied.
We analysed the diploma. It appears in fact that its bottom part was not included during the photocopy process.
The BBC reached out to Mr Tinubu's team to get a copy of the diploma in question. They sent what they said was the only existing copy of the diploma. It is a black and white photocopy identical to what was submitted to Inec.
Another claim, made by a fact-checking organisation in Nigeria, was that the diploma Mr Tinubu submitted was not from CSU as its diplomas do not include the phrase "with honors" under the degree name.
But the BBC found that while this was not reflected in the other diplomas released by CSU, it does appears in Mr Tinubu's diploma issued in the early 2000s, which was authenticated by Mr Westberg during his deposition.
It has the words "with honors" - a match with the diploma with the same detail submitted by the president to Inec.
Mr Westberg said that the school could authenticate this particular diploma because it was still in its possession as it was never picked up.
Not every student graduates from university with honours. Mr Tinubu, as attested to by CSU in several court documents seen by the BBC, did graduate from CSU with honours.
The BBC contacted CSU with questions about its diplomas and it referred us to a statement that read in part: "We are confident and always have been in the veracity and integrity of our records regarding Tinubu's attendance and completion of graduation requirements".
Another allegation making the rounds on social media is that the person who attended CSU with the name Bola A Tinubu is female.
Mr Tinubu attended Southwest College (now known as Richard J. Daley College) before transferring to CSU in 1976. In Southwest's transcript, there is an "F" (for "female") in the column where gender is indicated, leading to claims that it was a woman who attended the school and Mr Tinubu "stole her identity". Mr Atiku's lawyer, Mr Kalu, alluded to this in a press conference last week.
However, in his deposition, Mr Westberg stressed that there was no confusion about the gender of the person who attended CSU as he was a male named Bola A Tinubu. He said the university used other factors other than the name to authenticate the student's identity.
According to him, the Social Security Number (SSN) in the transcript from Southwest College matches what it has in other documents in which the student's gender is clearly marked as male.
However, the released documents did raise questions about Mr Tinubu's birth date and the secondary school he attended.
One of the documents stated that Mr Tinubu attended Government College Lagos in 1970. However, information available on the school website stated that it was only founded in 1974.
Aside from the gender discrepancy, the birth dates in some of the released documents differ from the official birth date of President Tinubu, which is 29 March 1952.
His transcript from CSU has his date of birth as 29 March 1954. His undergraduate admissions application form has his date of birth as 29 March 1955.
Mr Atiku's lawyer said during Mr Westberg's deposition that on the forms submitted to Inec, Mr Tinubu had given his date of birth as 29 March 1952.
Mr Westberg, during cross-examination, responded that the discrepancies could have been due to human error.
We contacted Mr Tinubu's team for comment about these discrepancies and a spokesperson directed us instead to his party - the All Progressives Congress. We then contacted Mr Tinubu's presidential campaign spokesperson Festus Keyamo, who is also a minister in the government. He did not take our calls or respond to our text and WhatsApp messages.
We also sent questions to Mr Abubakar's team. They did not respond.
By Chiagozie Nwonwu & Fauziyya Tukur & Olaronke Alo, BBC
Related story: Opposition claims president Tinubu forged diploma
