The development comes as the gang who murdered Ryan has been gripped by "major internal paranoia" over fears that at least one member is talking to gardai.
Alan's brother Vinny Ryan (23) is understood to have been based in Glasgow for the last six weeks where he has been joined by his older brother, Dermot.
However, unlike Vinny, Dermot has been spotted back at the family's home in Donaghmede in recent weeks.
He has also been doing "security" work at a Co Kildare pub.
Recently it emerged that dissident Republican gangs were working with local organised crime gangs in Scotland to generate funds, according to research.
And a small splinter dissident Republican faction loyal to the Ryan brothers has stepped up a campaign of extortion in recent weeks, the Herald has learned.
Alan Ryan was shot dead by the drugs gang led by so-called "Mr Big" in September, 2012, after a massive cash row between the two mobs.
In October, Vinny and close pal Darragh Evans (23) were cleared by the Special Criminal Court of charges of possession of an assault rifle and a handgun at Clonshaugh Walk, Coolock, on September 15, 2011 – the same day drugs trafficker Michael 'Micka' Kelly was shot dead.
Kelly, nicknamed 'The Panda', had been in a deadly feud with Alan Ryan after he refused to cough up a five-figure cash sum to Ryan's Real IRA extortionist gang.
The non-jury court ruled there was an insufficient evidence from which a jury could find Vinny Ryan and Evans were guilty beyond a reasonable doubt.
The court heard a garda probe began after the execution of Kelly on Marsfield Avenue in Clongriffin.
Gardai who searched a Saab 95 car recovered near Marsfield Avenue found an AKM assault rifle, an AK-47 style ammunition magazine, a Webley revolver and a Nike bag containing a lid from a Pringles crisp container.
Forensic scientist Dr Fiona Thornton told the court that a DNA profile matching that of Evans was found on the assault rifle and on the Pringles foil lid, while a DNA profile matching that of Vinny Ryan was found on the AK-47 style magazine.
However, under cross-examination she also agreed the incomplete, low-level DNA profiles could have been deposited by secondary or tertiary transfer.