Gardai said the happy-go-lucky victim was stabbed in the chest before his attacker set fire to the Ravensdale Close property in a desperate bid to destroy evidence.
The murder weapon -- a large knife -- was sticking out of his body when it was found by gardai. Gardai have obtained CCTV footage of a man buying Zippo lighter fluid one hour before the murder.
The footage was taken at a shop close to the Dublin City Council complex where the victim lived.
It shows a man buying a canister of the flammable liquid shortly after 12.30pm on Saturday.
The man is seen approaching the counter and buying Zippo lighter fluid, a Yop drink and cigarettes.
The suspect -- who is a drug addict and who has a number of previous convictions -- was recently released from Mountjoy Prison where he served a nine-month sentence for a knife-related offence.
Boylan, of Leighlin Road, Crumlin, previously received a jail sentence for stealing an 82-year-old hospital patient's wallet as he lay on an A&E trolley awaiting treatment.
Dublin District Court heard in November 2010 that Boylan reached under the patient and removed his wallet from his jacket pocket in the incident at St James's Hospital.
He then helped himself to the €250 the man had and stuffed it into his trouser leg. The 82-year-old had noticed the accused bending down and "messing around with something" under his trolley.
After Boylan had gone, the man noticed that his wallet, containing the cash, had been taken from his jacket.
Boylan was pointed out to the garda by both the victim and the security guard.
When searched, the money was found inside the lining of his trousers. The wallet was also recovered.
On that occasion, Boylan was also convicted of possessing of a knife in a separate incident. The court heard he had been attacked by youths in Crumlin on January 21 and called gardai.
However, when they got there and searched him, they found the knife in a washbag inside his backpack.