Despite the allegations of corruption that followed him for much of his career—and resulted in his being returned to uniform police duties before retirement and then facing a failed prosecution after it—Eist was never convicted of any such crimes.

[4] In 1967, Eist, then a sergeant based in Cheshunt, was awarded the British Empire Medal for bravery in single-handedly disarming an armed suspect.

A man with a rifle was observed in the property's basement, subsequently escaping into the back garden, where he proceeded to sit on a wall and threaten to shoot the officers if they approached.

[5] The gangster Freddie Foreman described Eist as a "rebel cop", who would get drunk and stand on pub tables singing.

On 8 June Ray was arrested at London Heathrow Airport attempting to leave for Brussels on a false Canadian passport.

[16] Ray was placed in the personal custody of Eist,[15] first being held at Canon Row Police Station and then in Wandsworth Prison.

Eist helped Ray acclimatise to the British prison service, for example, by arranging for him to receive cutlery—which had initially been withheld in his custody for fear of suicide—and bringing him magazines.

[20] Two years after his retirement, Eist testified under oath to the United States House Select Committee on Assassinations (HSCA) on 9 November 1976 – its first day of public evidence[20] – that Ray had mentioned disposing of a gun[21] on account of how Ray "had seen a policeman or police vehicle and thrown the gun away".

[23] Eist also reported that, while in British custody, Ray "seemed quite elated" – "brimming with confidence" – particularly as he believed he would receive payouts for television and media appearances.

[26] One of the House Committee members, Chris Dodd, however, said he was "extremely disturbed" that Eist had not come forward with his evidence regarding Ray when the HSCA re-opened its investigations in 1977.

Eist's answer – "in clipped tones" – was that he had been entangled in domestic affairs, namely his recent trial for corruption.

Among his informers, he counted men such as Roy Garner, who was later convicted of smuggling cocaine,[11] and became both a supergrass[note 5] and a millionaire.

[29] Eist tried to avoid making appearances in court wherever possible but would ensure that reward payments always included his informant's 10%.

[34] Journalist Paul Lashmar has described Eist as "by reputation the most corrupt Yard officer of the 1950s to mid-1970s which was no small achievement in such a packed field".

[35] Writer James Morton interviewed a Detetective Sergeant who told him that, notwithstanding that he had a second-to-none knowledge of the criminal scene and its players, Eist would have been unable to "get information without going some way towards them.

[38] Likewise, crime journalist Duncan Campbell suggests that Eist was "one of the most active bent officers" of the period.

[39] Kirby also suggests that "Eist's probity was also questionable", and describes occasions on which individuals were arrested for crimes that his informers had committed.

[8] Reg Dudley – a North London "career criminal"[39] who was wrongfully convicted of double murder in 1977 – was a fence during the 1960s and had, he wrote, a "close relationship" with Eist, whom he calls "bent".

Lane told the committee that Eist had been "dismissed in disgrace" from Scotland Yard, and cited charges of corruption, perjury and robbery: "if you knew of this man's background, you have done a disservice to the American people by raising the charges" he argued, and considered that accepting Eist's evidence at face value amounted to "perhaps the most outrageous thing this committee has ever done".

He suggested that Lane's allegations were a defence strategy to shift culpability for King's assassination onto the FBI, who, Eist said, "could not have acted more honourably to get that man brought to justice" and that "absolutely no way" had they been involved.

[43] In 1971, Eist headed one of the four teams investigating the Baker Street robbery, in which a gang tunnelled from a West End restaurant in the vault of a Lloyds Bank.

In 2021, two Daily Mirror investigative journalists, Tom Pettifor and Nick Sommerland, alleged that Eist took a cut of the takings "in exchange for protecting the gang".

[47] One of Eist's last high-profile successes came in January 1975 when he was commended for "outstanding diligence and detective ability leading to the arrest and conviction of an active and violent gang of robbers".

[48] The author Gordon Bowers describes Eist as being "under a cloud" over alleged corruption in the last years of his career,[39] for which he was investigated by Detective Chief Inspector Alan Rattray, although no charges were brought.

[50][47] Officers involved in Operation Countryman – the investigation into corruption within the Metropolitan Police instigated by Sir Robert Mark in 1978 – believed Eist to have received jewels from the Baker Street robbery,[41] among others.

One, Michael Gervaise, made the "startling allegation" to a court in 1982 Eist was one of several high-ranking police officers bribed and who had "actively participated in robberies as part of [Gervais'] gang".

[12]Conversely, Pettifor and Sommerland cite one of their sources as arguing that "Eist was a complete scoundrel but in those days you wouldn’t last in the CID if you wasn’t crooked, they had no straight runners around there".

[47] They also reported that on one occasion Eist auctioned procceds[47] from the 1975 robbery of the Bank of America, Mayfair,[56] in the basement of Paddington Green Police Station.