The Irish Sun can reveal two women close to the depraved brothers have been sleeping with a string of young Limerick thugs in a bid to recruit them as killers.
The female mobsters, who we can't name for legal reasons, want their former friend murdered at all costs.
Last Friday, brutes Wayne, 33, and John, 29, were convicted of threatening to kill members of April's family, for which they face up to ten more years behind bars.
But now the blood-soaked savages fear April will testify against them for ordering at least FOUR gangland murders — including those of innocent victims Shane Geoghegan, 28, and Roy Collins, 35.
And a senior security source told the Irish Sun last night: "The Dundons are terrified April can now obliterate them for once and for all.
"She has first-hand knowledge of several murders and attempted murders.
"By the time she's finished testifying, the Dundons and their associates might never get out of prison again.
"That's why their female pals have been bedding a string of young fools around Limerick and recruiting them to kill April and stop her talking.
"These girls are obviously pretty good in bed because these young fools are prepared to do anything for them — as long as they get plenty of sex."
April, 24, who lived with Ger Dundon for eight years and was privy to Murder Inc's darkest secrets, has agreed to tell all she knows.
She's said to be a "dead woman walking" since deciding to do the unthinkable — turn State's witness against her ex's psycho siblings.
Last month, April helped to convict Murder Inc hitman Barry Doyle, 25, for the murder of innocent rugby player Shane Geoghegan in 2008.
She made the decision to become a supergrass after John and Wayne Dundon threatened to kill her and members of her family, including her ma, her gangster da and her brothers.
They made the chilling threats when they learnt she was having an affair with gang-rapist Thomas O'Neill, 24, after brother Ger, 25, was jailed for five years in February 2011.
April had dumped the father of her three children — and refused to bring their young kids to see their da in prison.
Her mother Alice, 48, and her younger sister also gave evidence of being threatened by the lardy mobsters.
During the trial, Alice said Wayne told her his bro John would "give some fool ten grand" to kill her son Jimmy.
She said Wayne then told her his face would be the last her gangster son Gareth, who'd also been a member of Murder Inc, would see — "because I'm going to kill him myself".
He also warned her: "You're digging your own grave; it's very easy to make people disappear." Mr Justice Paul Butler said the Special Criminal Court found April's evidence to be fully believable.
He said the court was also impressed by the "entirely credible and convincing" evidence of her mother Alice, and was satisfied beyond a reasonable doubt Wayne had intimidated and made threats against her.
Although heavily pregnant with sicko O'Neill's twins and living under constant armed Garda protection, April is determined to help cops smash Murder Inc once and for all.
Despite her condition, Collins insisted on being present in court to see the three judges deliver their verdicts against the Dundons last Friday.