Gardai are probing whether another man picked up a dole payment for a 31-year-old missing man, who has not been seen for weeks.
Sources have revealed that detectives have obtained CCTV of the possibly sinister transaction, which happened on a date in mid-August.
Gardai are extremely concerned about the welfare of homeless man Stephen Sherlock and are investigating all relationships that he was involved in including with a female who has links to one of the country's most dangerous crime families.
Sources said that officers were also given a possible sighting of Mr Sherlock in the Dublin city area in recent days and they are investigating these claims as well.
The Herald revealed last week that gardai were investigating reports that he may have been pushed into a Dublin canal after getting into an argument with drinking companions.
It was revealed that officers are investigating reports that Mr Sherlock may have been pushed into the water in the Portobello area of south Dublin a number of weeks ago.
It is understood that garda divers have carried out searches of the Grand Canal in an attempt to find a trace of Mr Sherlock, who had been living homeless in the capital's centre, but no trace of him was found.
"This is being treated as a suspicious disappearance.
"The dole issue is just another aspect of it. Everything is speculative until evidence is obtained.
"Information has come in that he may have been pushed into the canal after getting into a row while drinking cans in the Portobello locality," a source said.
"However, there is no proof of that or any evidence that he is dead, but gardai are very concerned about his welfare," the source added.
Mr Sherlock, who is originally from the Pearse House flats complex in the south inner city, was reported missing by a male relative on Tuesday of last week.
It has emerged that he has not collected his social welfare payments since a date in August.
It is now being investigated that the last time his social welfare was collected was by a man other than him and CCTV is being studied.
Gardai launched an official appeal for information on the case last Wednesday.
"Stephen is described as being 5'10" in height, of medium build with short brown hair. It is not known what Stephen was wearing when he went missing," a spokesman said in a statement.
"Gardai are seriously concerned for Stephen's welfare and anyone with information is asked to contact Kevin Street Garda Station on 01 6669400, The Garda Confidential Line 1800 666111 or any station."
A major part of the probe has been the making of enquiries with homeless people.