Pakistan's Supreme Court has ordered an immediate police investigation into a gun attack which wounded opposition leader Imran Khan. The former prime minister was shot in the leg while leading his supporters on a protest march last Thursday. One person was killed and at least 10 injured in the attack on his convoy. Imran has accused the current prime minister, interior minister and an army general of plotting to assassinate him. All of them deny the allegation. The former prime minister has said police in Punjab province, where the attack took place, were insisting he withdrew a reference to the army officer — who holds a senior position in Pakistan's ISI intelligence agency — before they investigate his accusation. The country's top judge wanted to know why police had not begun a formal investigation four days after the shooting — and gave them 24 hours to do so. "If the police did not investigate, the evidence may have been destroyed at the crime scene. This way the evidence of the case will be controversial and will be unacceptable in court," said Chief Justice Umar Ata Bandial. Imran, former prime minister and head of political party Pakistan Tehrik-e-Insaf, said the march will resume without him on Tuesday. Imran, 70, has been recovering in hospital after being shot at the protest march in Wazirabad in the northeast. Video footage showed him and his supporters on a shipping container being towed by a lorry before a burst of gunfire is heard. Imran is then seen ducking, as those around him try to cover him. One suspect remains in custody but no charges have been laid. The march on the capital — which was on its seventh day at the time of the attack — was suspended after the shooting last week, but is due to resume on Tuesday. Imran, ousted from power in a parliamentary vote of no confidence in April, said he will not join it while he recovers from his injuries. He and his supporters have renewed their call for fresh elections, which are due by late next year. The political turmoil in Pakistan comes as it reels from economic crisis and the effects of devastating floods this summer. The country has a record of political violence, with former Prime Minister Benazir Bhutto assassinated in 2007. Many recalled her killing in the wake of the attack on Imran. The former cricketer-turned-politician, who still commands widespread support, has been at loggerheads for months with the current government led by Shehbaz Sharif. Last month the election commission disqualified him from holding public office in a case he described as politically motived. — BBC