Journalists chase an armoured vehicle carrying Rao Anwar. — AP
The bench has also ordered the formation of a new five-member joint investigation team, headed by Additional IG Aftab Pathan, to probe Mehsud's killing.
On Anwar's request, it also ordered the authorities to unfreeze Anwar's bank accounts so his children do not face financial difficulties.
Anwar's salary must also be paid, the CJP said after the officer was taken into custody.
He said no institution, including the judiciary, will influence the investigation, which he said "must be transparent."
Anwar has 'done no favours' by surrendering: CJP
On Anwar's counsel's request, the court withdrew the contempt notice issued to the officer last month, but ruled that his name will remain on the Exit Control List until the probe is completed.
The court in its order said that Inspector General of Police Sindh A.D. Khowaja will be responsible for Anwar's protection till the conclusion of the case and Mehsud's relatives will not create any difficulties for the ex-SSP Malir.
Anwar had arrived at the court under tight security and was taken directly to Courtroom number 1, where the hearing into Mehsud's murder case took place. It is not yet clear whether he had shown up to court voluntarily.
IG Khowaja was also present in court for the hearing.
"We had heard many tales of your bravery," the chief justice said at the outset of the hearing, "but if you are so brave, where had you been hiding like a coward all these days?"
The former SSP Malir replied that he was facing "some threats" which he had mentioned in a letter sent to the CJP.
"I am guiltless and am being framed in this case," he claimed.
His counsel, Shamim Rehman, informed the bench that Anwar had now "surrendered".
But Justice Nisar remarked that Anwar had "done no favours" by surrendering, and it had been inappropriate of him to write letters to the CJP.
"Prove your innocence before the [new] joint investigating team," he told Anwar, adding that he would be considered innocent till proven guilty in the eyes of the law.
Back to Karachi
Later in the day, Karachi police brought former Anwar back to the city under strict security.
Police are likely to present the former SSP Malir before the court on Thursday in order to obtain his physical remand.
Meanwhile, an official informed Dawn that police have already conducted investigations in cases pending against Anwar.
“The JIT formed on the orders of apex court would conduct further probe in case there is any new development,” he said.
'Staged encounter'
Naqeebullah Mehsud — whose name was given as Naseemullah on his national identity card — was a shop owner fond of modelling, relatives of the deceased had told Dawn.
Hailing from South Waziristan, he was among four suspects killed in an 'encounter' with a police team headed by Anwar in the Usman Khaskheli Goth on the outskirts of the metropolis in January 2018.
Anwar had alleged that Naqeebullah was a Tehreek-i-Taliban Pakistan (TTP) militant, but a later statement reportedly issued by a spokesperson for TTP's South Waziristan chapter had termed the claim "baseless", clarifying that the deceased had no links with the banned militant outfit.
Naqeebullah's family had also disputed Anwar's claim, saying that the 27-year-old had no links with any militant organisation.
In January, an inquiry team of senior police officers probing the alleged extrajudicial killing of Mehsud had found that the Waziristan native was killed in a fake encounter which was staged by then-SSP Malir Anwar on January 13.
The high-level inquiry committee had also concluded in its initial report submitted to the Sindh police that the deceased man had no militant tendencies.