Two guns, ammunition and property including paintings and antiques were seized in raids across four counties conducted by armed gardai.
Among 30 properties searched were a west Dublin hotel managed by businessman Jim Mansfield Jnr, a number of apartments in the Citywest complex and the offices of solicitors and accountants.
Searches also took place yesterday morning at Tassagart House, a Georgian mansion in Saggart, Co Dublin, which was owned by Jim Mansfield Snr, who died there after an illness in January last year.
Last night it emerged that €50,000 in cash was seized in the massive operation that took place at locations in Dublin, Kildare, Louth and Cork.
Senior sources said it was "mainly a money-laundering investigation" led by the Organised Crime Unit.
It is understood that €30,000 in cash was discovered at one property in the Citywest area.
An original print by Pablo Picasso was found in a strongroom in the same property.
Sources said dozens of officers will spend the next few weeks examining a "vast amount of documentation" that was seized along with a number of computers.
"This investigation has been going on for over a year," a senior source said, adding that it will continue for some time to come.
No arrests were made yesterday and there were no incidents during any of the searches.
Sources said there are no plans for any arrests in the near future.
It has emerged that some of the paintings and antiques were seized at the Finnstown Castle Hotel in Lucan which is managed by Mr Mansfield Jnr.
Elsewhere, two firearms seized by gardai were confirmed last night as a shotgun and a pistol.
Revenue investigators and Criminal Assets Bureau officers were also involved in yesterday's operations.
Last May a large bomb was discovered at the hotel which forced the evacuation of a wedding, but that incident is not linked to yesterday's raids.
Detectives from Clondalkin Garda Station warned Mr Mansfield last October that there was a threat against his life.
Sources said the associates of a notorious Traveller criminal had been approached about a possible attack. These associates were linked to slain criminal 'Fat Andy' Connors.
However, in an interview with the Herald, Mr Mansfield denied his life was in any danger or that gardai had told him so.
He said he believed no criminals are after him or want to see him dead.
"I wouldn't see any reason why anyone would want to harm me," he said at the time.
Insisting that he has "bigger worries", a defiant Mr Mansfield claimed a threat to his life is "news to me".
Mr Mansfield was a regular on the celebrity social scene at the height of the Celtic Tiger years.
He had a relationship with model Katy French, who collapsed and died after taking cocaine in the house of businessman Kieron Ducie in December 2007.