A US federal judge dismissed a lawsuit against Saudi Crown Prince Mohammed bin Salman in the killing of US-based journalist Jamal Khashoggi, bowing to the Biden administration’s insistence that the prince was legally immune in the case.

District of Columbia US District Judge John D Bates heeded the US government’s motion to shield Prince Mohammed from the lawsuit despite what Bates called “credible allegations of his involvement in Khashoggi’s murder”.

A team of Saudi officials killed Khashoggi inside the Saudi consulate in Istanbul in 2018. Khashoggi, a columnist for The Washington Post, had written critically of the harsh ways of Prince Mohammed, Saudi Arabia’s de facto ruler.

Jamal Khashoggi, who wrote critically about the Saudi crown prince, was murdered inside the Saudi Consulate in Istanbul in October 2018. Photo / AP

The US intelligence community concluded the Saudi crown prince ordered the operation against Khashoggi. The killing opened a rift between the Biden administration and Saudi Arabia that the administration has tried in recent months to close, as the US unsuccessfully urged the kingdom to undo oil production cuts in a global market racked by the Ukraine war.

Khashoggi had entered the Saudi consulate to obtain documents needed for his upcoming marriage. His fiancee, Hatice Cengiz, who had waited unknowingly outside the consulate as he was murdered, and a rights group founded by Khashoggi before his death brought the lawsuit. The lawsuit also named two top aides of the prince as accomplices.

The Biden administration, invited but not ordered by the judge to offer an opinion on the matter, declared last month that Prince Mohammed’s standing as Saudi Arabia’s prime minister gave him sovereign immunity from the US lawsuit.

Saudi Arabia’s king, Salman, had named Prince Mohammed, his son, as prime minister weeks earlier. It was a temporary exemption from the kingdom’s governing code, which makes the king prime minister.

Khashoggi’s fiancee and his rights group argued the move was a manoeuvre to shield the prince from the US court.

• Khashoggi murder: Saudi Arabia admits killing was 'premeditated'
• Bryan Fogel: The story of murdered journalist Jamal Khashoggi
• 'He would be convicted in 30 minutes': US senators take aim at Saudi prince

Bates expressed “uneasiness” with the circumstances of Prince Mohammed’s new title, and wrote in Tuesday’s order that “there is a strong argument that plaintiffs’ claims against bin Salman and the other defendants are meritorious”.

But the government’s finding that Prince Mohammed was immune left him no choice but to dismiss the prince as a plaintiff, the judge wrote. He also dismissed the two other Saudi plaintiffs, saying the US court lacked jurisdiction over them.

The Biden administration argued long-standing legal precedent on immunity for heads of government from other nations’ courts, in some circumstances, demanded that the prince be shielded as prime minister, regardless of the prince only recently obtaining the title.

The Biden administration already had spared Prince Mohammed from government penalties in the case, again citing sovereign immunity. Rights groups and Saudi exiles argued that sparing Prince Mohammed from accountability in Khashoggi’s killing would give the crown prince and other authoritarian rulers around the world a green light for future abuses.