"In certain people's minds it may have appeared like there was an issue which clearly there wasn't in relation to me and it was disappointing to have my efforts questioned. In fact when I say disappointing it was outrageous really."
"It is a return to sanity really and with regards to the contracts generally, well I am extremely pleased that they are going to be changed but I guess the proof is in the pudding in their [actions] and we will have to see what happens there," Dr Gilbert said.
"It was important to get an apology and it is not just a symbolic thing but for me it sends a message to the public that they have made a grave error and they accepted that.
Having my research questioned was professionally very compromising and I wasn't going to have that."
Dr Gilbert said despite his recent dealings with Police, he would "take them at their word".
Gilbert is the author of the award-winning book Patched: The History of Gangs in New Zealand and lectures on the subject.
He was seeking crime data to investigate the link between liquor outlets and crime rates when he was banned due to his gang links.
Dr Gilbert said his association with gangs was for research and he had not done anything he could be charged for.
The clash between Dr Gilbert and Police also revealed a contract giving officers the power to "improve" research which shows "negative results" and then "veto" its publication which had to be signed by all academics wanting access to data.
Evans said that contract would now be changed and guidelines around vetting of researchers amended, including high-level oversight and more detailed case-by-case consideration on vetting checks on researchers which are negative.
Any language that may be interpreted as restricting the independence of academic research would also be removed.
Evans said the agreement was never intended to restrict "academic debate".
"Police has clear obligations to appropriately manage information which is of a private, security or operationally sensitive nature.
"We must also manage the demands on Police to provide this information, which in the case of research projects can often be a complex process requiring significant Police resources," Evans said.
"It has always been our intention to balance the need to appropriately manage access to such information while enabling academic research to take place."