Remorse is the very least that Gatlin should be showing for an athlete associating with Mitchell
In his reformed man phase, Justin Gatlin has made great play of following a righteous path, touring schools and colleges for the US Anti-Doping Agency to deter young athletes from repeating his transgressions.
With this in mind, his victory over Usain Bolt at this year's world championships in London was depicted in one American account as "total redemption".
So why was this born-again paragon of virtue still associating with a figure like Dennis Mitchell?
For anybody hoping for a day of absolution in athletics, Mitchell is bad news.
Not only did he compete in one of history's dirtiest races, the 100 metres Olympic final in Seoul that brought Ben Johnson's 9.79 seconds of infamy, he also offered one of sport's most eye-watering excuses.
After testing positive for testosterone, Mitchell claimed to have had "five bottles of beer and sex with my wife at least four times" the night before his urine sample.
"The lady deserved a treat," he said. US Track and Field accepted this, until the IAAF restored some measure of sanity by banning him for two years.
And yet Gatlin somehow perceived Mitchell, a throwback to the endemic doping of the Eighties, who also admitted during the Trevor Graham trial to having taken human growth hormone, as part of his ticket to rehabilitation.
The two were uncommonly close.
In London, Mitchell told Olympic writer Alan Abrahamson this about his student: "Humility is about life and humility is what you make of it.
"He got to the point where he wanted to do something that was bigger than himself. You have to share it or lose it.
"At this point in his career, he was willing to humble himself to give some of it away to keep all of it."
Of his relationship with Gatlin, he added: "It's a love story."
One does not imagine that Richard Curtis will be buying up the rights any time soon.
For too long, athletics has been far too dilatory about disowning Mitchell and his ilk.
He is a drug cheat whose toxic past should have barred him from every coaching job in the land.
So, what did the Americans do to show they had moved on? They made him the director of the national relay programme, of course, without any plausible formal justification for why.
"Dennis was vetted by our high performance team," a US spokesman said, with groundless confidence.
Those vetting processes were clearly about as rigorous as the doping controls that Robert Wagner, an agent connected to Gatlin, has boasted of being able to sidestep so effortlessly. Describing the supposed ease of procuring performance-enhancing drugs, he told undercover reporters for The Daily Telegraph: "You think Justin is not doing this?
"Do you think Dennis wasn't doing this? Everybody does it."
Gatlin has denied any wrongdoing.
In athletics, grisly patterns of the past have an uncanny habit of repeating themselves.
The sport's chiefs assumed that the example of the East Germans, who by state edict pumped shot putter Heidi Krieger full of so much Oral-Turinabol that she later underwent a sex change, could never be repeated.
But then along came the Russians and their system of administering drugs as if they were optics on a cocktail bar: Chivas whisky and steroid mixture for the gentlemen, and dirty Martinis for the ladies.
It is the same, regrettably, with Gatlin and his former mentor Mitchell, abruptly sacked in response to this latest investigation.
Mitchell's response to his doping disgrace was distinguished only by the dearth of contrition.
About the nearest he came to an apology was when he said he was "peer-pressured into making bad choices" at one of Graham's training camps in North Carolina.
Gatlin, likewise, has tended to blame everybody but himself.
He ascribed his first positive test, for amphetamines, to his diagnosis with attention deficit disorder.
On that occasion, many gave him the benefit of the doubt. But when he tried to pass off his second in 2006 - for testosterone - on a cream rubbed into his buttocks by a rogue masseur, he was roundly ridiculed.
So when Gatlin wonders why he does not feel the love outside America, and why crowds in London last summer hissed at him as if he was the Big Bad Wolf, it might be because he has so consistently avoided the word "sorry".
Couple this with the fact that he kept Mitchell on the payroll, and one starts to understand why, in his latest difficulties, sympathy is in the shortest supply.
We have seen this play too many times before. (© Daily Telegraph, London)