Father Pat Keegans, who lived in the Dumfries and Galloway town, wrote an open letter to families of US victims seeking their support for a fresh probe into the 1988 terror attack on Pan Am flight 103.
It follows a petition at the Scottish Parliament urging a new investigation into the conviction of Abdelbaset Ali Mohmed Al Megrahi, the only man found guilty of the atrocity.
Megrahi's release on compassionate grounds last year split opinion and caused anger in America where many victims' families live.
Father Keegan's letter calls them to "show your concern" for views held by those who dissent from the verdict, it was reported.
The letter added: "Your certainty in the validity of the trial and conviction should allow you accept that such an inquiry would vindicate your belief and you should have nothing to fear from it."
It continued: "There has been a conviction which is not universally accepted but has been questioned by many. A full, public, independent inquiry into all aspects of the bombing would assist us in finding truth and justice."
Dr Jim Swire, whose daughter Flora died in the bombing, asked MSPs on Holyrood's Petitions Committee to push for an inquiry earlier this month. He backed Father Pat Keegans' attempts, hoping for an "objective look" at the evidence.
Dr Swire said: "I think in the long term, some degree of truth is going to come out. I agree with what Pat Keegans has been saying but there will be some risk. The longer the truth takes to come out, the harder it will be for some people."
Cardinal Keith O'Brien, the leader of the Roman Catholic Church in Scotland, backed the campaign and said that without such a probe the "web of mystery" may never be resolved.
About 1,500 people signed the petition from the Justice For Megrahi pressure group.
Father Keegans, administrator of St Margaret's Cathedral in Ayr, said he decided to write the open letter after Cardinal O'Brien was criticised in America.
The priest lived at Sherwood Crescent in Lockerbie when the street was hit by debris from the aircraft, killing residents.
He said: "I thought I should reply. I thought it would be better to reply to them all. I wanted to say to the Americans that we have legitimate views here too."
He said he understood the desire among some families to accept the verdict and that people wanted to move on. But he added: "It keeps coming up. It didn't stand up to serious scrutiny. It won't go away."