One of the men — a senior gangland figure — was from Finglas, north Dublin, while the other man was killed in Finglas.
In a third investigation, a young man escaped with his life in Finglas after being shot by gunmen on a motorbike.
None of the incidents are believed to be linked.
Meanwhile, a man remained in critical condition after being seriously assaulted in the north inner city.
Yesterday’s events began when a man’s body was spotted near a busy junction in Finglas at 5.15am. The man, named locally as Maurice Martin, had been stabbed a number of times.
Martin, 21, had addresses in O’Devaney Gardens flat complex in the north inner city and, more recently, in Kells, Co Meath. According to local sources, he was drinking with other people in a nearby field overnight.
Apart from crimes committed as a child, he did not have many convictions.
Just after noon yesterday, gardaí recovered a body in a ditch in a field just off the M1 Dublin-to-Belfastmotorway near Lusk, north Dublin.
Paul Smith was a senior criminal from Finglas and was a suspect in the murder of Graham McNally in Finglas last January. The 34-year-old was a lieutenant in a gang run by Paul “Farmer” Martin, from Kippure Park in Finglas, who was shot dead by a local gang boss last August.
Smith was married into the Martin family and gardaí are investigating if he was shot in retaliation for McNally’s murder.
There was one other gangland murder in Finglas this year — that of Michael Murray last March — and 10 since the start of 2006.
At about 5.15pm yesterday, a young man was shot by assailants travelling on a motorbike in Casement Park in Finglas.
Eyewitnesses, including young children out playing, saw the gunmen open fire, injuring the victim in the behind. He was taken to Mater Hospital, where his injuries are described as not life-threatening.
Meanwhile, in the north inner city, a 34-year-old man is in critical condition after being seriously assaulted on Thursday night.