Barrack Obama's half brother Malik has released a picture of what he claims is the former US president's Kenyan birth certificate. The dubious document was uploaded to Twitter on 9 March in an apparent attempt to reignite the birther debate.

It is not known where Malik acquired the document though its validity is highly questionable. In 2011 the White House issued a long-form version of President Obama's Hawaiian birth certificate in response to a conspiracy theory that he was born abroad.

Were the conspiracy – coined the "birther movement" – true, it would have made Obama's presidency illegitimate. Donald Trump was the movement's most famous advocate but he has since publicly acknowledged that Obama was born in the US.

Malik has been a vocal supporter of Donald Trump and his Twitter profile picture shows him wearing a signature red "make America great again" hat.

The unverified and, almost likely, dubious 'birth certificate' produced by Malik alleges that his half brother was born at Coast Province General Hospital in Mombasa on 4 August 1961 – the exact same day given on Obama's Hawaiian certificate. The names of Obama's parents are also identical on both documents .

The US constitution states that people born outside the US cannot become president. The birther movement was a constant thorn in Obama's side throughout his time in office even after the White House produced his Hawaiian birth certificate.