The 55-year-old father was shot dead as he stood at the doorway of his wife Yumei’s shop on Bridgefoot St in Dublin’s south inner city.
Their 14-year-old daughter was understood to be inside the Shoetown store at the time of the gun attack, shortly after 4pm, in the Liberties area of the city.
Gardaí are investigating if the murder was linked to a dispute within a drugs gang in Cabra, north Dublin, where the deceased lived, or if it was connected to the Kinahan-Hutch feud.
The convicted gunman, armed robber and drug dealer escaped murder in a previous shooting in Cabra last November.
Speaking at his homily at the Church of the Most Precious Blood in Cabra, Fr Damian O’Reilly said the deceased was “born into a loving family” 55 years ago.
“Some choices he made were very good choices, especially his decision to marry Yumei and having the wonderful gift of his daughter,” said Fr O’Reilly.
“Other choices he made in his early life were not the best choices for his life.”
He said the wish of the family was “not so much to talk about David but rather to pray for him”.
Mr Douglas received a 12-year sentence for armed robbery and shooting with intent to murder a garda in 1983, and a 10-year sentence, with five suspended, for drug trafficking in 2010.
“As we come to lay David to rest we silently smile as we recall his happy moments in his life and we reflect on some of the bad decisions he made which resulted in the torments that life had inflicted on him resulting in his tragic death.”
He said what Mr Douglas wanted most was to walk his dog and walk in peace in the safety of his family.
Mr Douglas was associated with a significant drugs gangs based in the Cabra area and gardaí suspect his murder, and that of fellow gang associate Darren Kearns last December, could have been part of that feud.
They are also investigating if the murder was carried out by two gunmen acting for the Kinahan cartel.
Mr Douglas was wrongly implicated in a botched gun attack on Kinahan lieutenants last November.
Gardaí have appealed to people who saw a silver/ grey Mercedes CLA, reg 161D 26702, used in the shooting, to contact 01 666 9400.