The IPCC said there was "no case to answer" for misconduct against the man who led a triple murder investigation arising from the riots in Birmingham in August 2011. Detective Chief Inspector Anthony Tagg was in charge of the criminal investigation.
However, the police watchdog did say the family liaision officer, Detective Inspector Khalid Kiyani, who retired in October 2012, "would have had a case to answer for gross misconduct".
The watchdog said both officers' record-keeping was "deficient".
Haroon Jahan, Shazad Ali and Abdul Musavir were killed when they were hit by a car in Winson Green during the riots in Birmingham.
It emerged during the trial that defence barristers were never told of an offer made by police of immunity from prosecution for witnesses involved in the disorder until the 10th week of court proceedings.
The IPCC said the Crown Prosecution Service had since concluded there was "insufficient evidence to provide a realistic prospect of proving that either police officer had knowingly made a false statement and as a result committed the offence of perjury".
Eight men were acquitted of the murders in July 2012.
The criminal investigation into the deaths of three men in the Birmingham riots was mishandled, according to the independent police watchdog, but it is unlikely any officer will face action over the failings.
Tariq Jahan's sentence was suspended for two years and he was ordered to complete 100 hours of unpaid work.
He was also told to pay £1,000 compensation this victim within 12 months.
Judge William Davis QC said: "People who break people's jaws in this kind of mindless violence normally go to prison but I take a view that because of his extraordinary position it is right to suspend sentence."
Addressing Jahan, he added: "There is in your case this extraordinary combination of events. For that reason and that reason alone I can suspend the sentence.
"Ordinarily this would mean that you would go to prison for 12 months but this all happened last July and in August, as everybody in this court knows, you suffered the loss of one of your sons, which was desperate in itself."
Father Tariq Jahan, who publicly appealed for calm after his son was killed in last summer's riots, has been given a 12-month suspended jail sentence.
He was convicted at Birmingham Crown Court of inflicting grievous bodily harm on a man he accused of staring at his wife.
The jury of seven men and five women took just under four hours to return a majority verdict against Tariq Jahan.
Jahan was cleared of the more serious charge of causing grievous bodily harm with intent.
His Honour Judge William Davis QC will sentence him this afternoon.
A bereaved father who publicly appealed for calm hours after his son was killed in last summer's riots has been convicted of a roadside attack after kicking and punching a factory worker he accused of staring at his wife.
Tariq Jahan, who is 46, was found guilty of inflicting grievous bodily harm following a three-day trial at Birmingham Crown Court.
Jurors heard he grabbed 34-year-old Sajjid Ali by the throat before punching him to the ground after the pair got into an argument in Handsworth, Birmingham, on July 6 last year.
The attack happened a month before Jahan won national acclaim for an impassioned appeal for peace after his 21-year-old son Haroon was killed during disorder in the Winson Green area of Birmingham.
Bereaved father Tariq Jahan, who publicly appealed for calm after his son was killed in last summer's riots, has been convicted at Birmingham Crown Court of inflicting grievous bodily harm after a roadside attack on a man he accused of staring at his wife.