Their entreaties are as strong now as in the days after the cowardly killing of the 22-year-old former US Marine on Phuket on August 14, 2010.
British citizen Lee Aldhouse, then 27, fled Phuket immediately after Longfellow's body was found.
Aldhouse, nicknamed ''Pitbull,'' was arrested when he arrived back in Britain soon after. Lawyers have since been resisting moves to extradite him back to Thailand to face trial on Phuket for murder.
British Home Secretary Theresa May approved the precedent-setting extradition of Aldhouse in December, but two judges subsequently allowed him an appeal to Britain's High Court.
On the other side of the Atlantic, Longfellow's family and friends still wait for news, growing more anxious as weeks and months pass.
Earlier this year, more than 500 of them signed an online petition asking the High Court to expedite the extradition: ''He took a life and should of (sic) thought of that before killing Dashawn.''
Aldhouse allegedly picked a fight with Longfellow at the Freedom Bar in Rawai, southern Phuket. When he lost the fight, he allegedly avenged defeat in the brawl by ambushing Longfellow and stabbing him to death.
Among the pieces of evidence is footage from a security camera at a nearby 7-Eleven store showing a man who looks like Aldhouse grabbing two knives, and leaving in a hurry.
Friends and family of Longfellow continue their pleas on an online tribute site to their dead son, brother and friend.
''It is time for Lee to pay for the hero he took from us,'' wrote Dashawn's brother, Marquis, earlier this month.
He added yesterday: ''If anyone has any info about the progress of this expediction (sic) of Lee please let us know I am going crazy waiting. It is time for our family to have JUSTICE for our FALLEN HERO DASHAWN.''
If for some reason the British High Court rejects the application for extradition to Thailand, Longfellow's family is expected to seek the help of the US Government to explore other options.