Gerard was shot dead by the UDA as he walked along the Floral Road in north Belfast in July 2002. No one has ever been convicted of murdering the 19-year-old, but the loyalist paramilitary gang said the attack was a "measured military response" to other sectarian attacks in the area.
His was the last murder of the Troubles, and the first to be investigated by the PSNI.
The Gerard Lawlor Community Inquiry was set up on the tenth anniversary of his death to look into the circumstances surrounding the fatal attack.
Mr Lawlor's family believe informants were involved in his murder and raised concerns about the police inquiry, including the possibility of collusion.
Gerard's father, John Lawlor said some evidence only came to light through the inquiry's investigations.
"It has been a help to us from the point of view of actually what occurred that night and the time lapse. I think when you look at the report itself it does warrant the questions that are being asked," he told UTV.
We’ve done our best and we’ve done everything possible to find out the truth about what happened.
John Lawlor
"We think about Gerard every day. He has four brothers there that are still a tight knit unit and his own son Josh.
"He's going to be looking for answers and I don't want to be in the situation later on in life when he says 'Granda, what did you do?'"
Jane Winter, Director of the British Irish rights watch, chaired the panel. She said they found "serious deficiencies in the various investigations that have taken place which in our view, add up to collusion" and the PSNI and Police Ombudsman "have all failed so far to provide an effective investigation".
"When the authorities wilfully refuse to look at the facts that are right in front of them that does amount to collusion," she told UTV.
"The Lawlor family have always had at the back of their mind that somebody is being protected. Now we didn't find any evidence of that we are not the police ourselves, we do not have those powers but the question has to be asked."
Panel member Professor Bill Rolston said he was shocked at their findings, and believes the newly-formed PSNI failed at their first test.
On the basis of the evidence that I saw that day at the inquiry, and have read countless times since, there's a clear pattern of failure starting from that evening and building right up to the present day.
Prof Bill Rolston
He believes Gerard's murder was the result of collusion, under Judge Peter Cory's definition which includes acts of omission.
"Not just the police, but the ombudsman and various other organisations have not taken advantage of the evidence that's sitting before them in relation to this," he said.
Sinn Féin MLA Gerry Kelly said questions need to be asked about the investigation.
"It was clear from the findings of this inquiry that Gerard Lawlor's killing was not properly investigated by the PSNI," said Mr Kelly.
"In fact the investigation was abysmal to say the least. The question being asked is: was it to protect informants, because there was collusion or because of sectarianism within the PSNI.
"I will be bringing the findings of this inquiry to the Policing Board. Even at this late stage there is an imperative to hold a proper investigation into Gerard Lawlor's killing. His family deserve that much."
A Police Ombudsman spokesperson said they are considering the contents of the report.
"We have not yet published the findings of our investigation into police conduct relating to the death of Gerard Lawlor. However, a review of our investigation was initiated a number of months ago and is ongoing.
"Once the review is finished and the new Police Ombudsman, Dr Michael Maguire, is happy that the investigation is complete, we will be in a position to publish our findings."
A police spokesperson said: "The investigation into the murder of Gerard Lawlor has been reviewed by the PSNI Serious Crime Review Team and is currently the subject of a PONI investigation and, as such, it would be inappropriate to comment."
They reissued their appeal for information about his murder.