KABUL -  Afghanistan’s embattled vice president Abdul Rashid Dostum has left for Turkey, officials said Saturday, in what could be another long exile for the former warlord following allegations that he raped and tortured a political rival.

Dostum, a powerful ethnic Uzbek warlord linked to a catalogue of war crimes, departed late Friday in the middle of a criminal investigation that has drawn attention to the culture of impunity that is hobbling Western-backed efforts to instil the rule of law in Afghanistan.

Speculation is rife that he has sought temporary exile in Turkey in a bid to escape prosecution, with observers saying it could mark the end of his checkered political career in Afghanistan.

But a spokesman for Dostum, Bashir Ahmad Tahyanj, insisted that he would return after visiting Turkey for “medical checkups and to visit his family”.

Dostum is accused of abducting rival Ahmad Ishchi last year during a game of Buzkashi - a type of polo played with an animal carcass - in northern Jowzjan province.

Dostum, 63, allegedly kept Ishchi hostage in his private compound for five days, where he was said to have been tortured and sodomised, an accusation that Dostum has denied.

Nobody was arrested or indicted despite reports that medical evidence backed Ishchi’s claims that he was abused.

The country’s attorney general launched an investigation into the allegations but Dostum evaded questioning by being holed up in his palace in central Kabul, guarded by his armed militiamen.

Afghanistan’s Western allies initially piled pressure on President Ashraf Ghani’s government to prosecute Dostum, who has survived all previous allegations of abuse.

But amid the public standoff it was clear the government favoured exile rather than a criminal trial against Dostum, which could trigger violence from his Uzbek support base.

Dostum’s aides alleged his office staff had not been paid by the government for months, in what was believed to be a pressure tactic to make him leave the country.

The development highlights what human rights defenders call a sobering reality of Afghan politics - some strongmen are simply too powerful to prosecute.

“It’s a stunning example of what has become standard practice in Afghanistan, not just for Dostum but for anyone in a position of power: having promised to deliver justice the government has shown itself ultimately unwilling to do so,” said Patricia Gossman, Afghanistan researcher with Human Rights Watch.

Earlier this month, another former warlord Gulbuddin Hekmatyar, who shelled Kabul during the civil war in the 1990s, returned to Kabul as part of a peace deal granting him immunity.

In 2008, Dostum was accused of abducting another political rival who had allegedly plotted to assassinate him. Dostum went into exile in Turkey after another long standoff until former president Hamid Karzai called him back.

Despite his human rights record, Dostum was invited to join the National Unity Government in 2014 in a bid by Ghani to attract the support of his Uzbek constituency.

In a brief statement presidential spokesman Shah Hussain Murtazawi said he wished Dostum “good health”. Dostum is believed to have an alcohol problem and suffers from diabetes.

But Murtazawi declined to comment when asked whether the president was in contact with Dostum before his departure.