Here's is a look at some of the new information revealed in Paulson's testimony and in the video:
1. Michael Zehaf-Bibeau's motive
Paulson said Zehaf-Bibeau recorded a video on his cellphone the morning of Oct. 22 while sitting in his car near Ottawa's downtown police station and Highway 417.
"To those who are involved and listen to this movie, this is in retaliation for Afghanistan and because Harper wants to send his troops to Iraq," Zehaf-Bibeau says in the 55-second video. Another 13 seconds at the beginning and five seconds at the end were cut out to protect the RCMP's ongoing investigation, Paulson said.
"So we are retaliating, the Mujaheddin of this world. Canada's officially become one of our enemies by fighting and bombing and creating a lot of terror in our countries and killing us and killing our innocents. So, just aiming to hit some soldiers just to show that you're not even safe in your own land and you gotta be careful," Zehaf-Bibeau continues.
"We'll not cease until you guys decide to be a peaceful country and stay to your own and stop going to other countries and stop occupying and killing the righteous of us who are trying to bring back religious law in our countries. Thank you."
Paulson said Zehaf-Bibeau was alone in the car when he shot the video.
2. Possibly influenced by others
In his prepared remarks and in a question and answer afterward, Paulson said the Mounties' investigation continues and isn't just limited to Zehaf-Bibeau.
"Permit me to say clearly that the RCMP is engaged in an active criminal investigation to either establish or refute whether anyone aided, abetted, facilitated, counselled or conspired with Zehaf-Bibeau to commit the crimes he did.
"The RCMP has over 130 full-time investigators and staff presently working on this case. We've interviewed over 400 individuals, from the people he associated with in B.C. to the people he rode the Greyhound bus with, to the people who saw him at the shelter in Ottawa.
"The active investigation is pursuing those who may have actively contributed to his development and his radicalization. In that sense I just want to frame up the investigation, we are actively investigating individuals who may have contributed to his crimes."
Paulson said there would have been opportunities for some of the 400 people to have contacted police earlier based on some of Zehaf-Bibeau's behaviour.
3. Police consider shooter a terrorist
Paulson said what Zehaf-Bibeau did is enough under current Canadian law to have charged him with terrorism-related offences.
"If Zehaf-Bibeau had not been killed but rather taken into custody, we would have charged him with terrorism offences … The RCMP believes on the evidence that Zehaf-Bibeau was a terrorist. Anyone who aided him, abetted him, counselled him, facilitated his crimes or conspired with him is also, in our view, a terrorist and where the evidence exists, we will charge them with terrorist offences.
"It's not relevant to us or our investigation what kind of a terrorist Zehaf-Bibeau was or if he was a particularly intelligent, sophisticated, influential or personally disciplined terrorist. To us, it all turns on the evidence we collect which we compare against the statute. What was he doing and why was he doing it?"
4. Rifle's origin unknown, and he had a knife
Paulson showed photos of Zehaf-Bibeau's rifle and knife.
"Upon taking possession [of his newly purchased vehicle], he drove to Mont-Tremblant [Que.] where he was seen with a long knife. Very early the next morning, Oct. 22, he was observed by witnesses placing a rifle in the trunk of his car. Hours later he shot and killed Cpl. [Nathan] Cirillo, got back in his car and stormed Parliament … We have not been able to confirm the origins of the gun.
"We are releasing a photo of the gun, which seems unique, in the hopes that someone might recognize it. I can confirm that he had a long knife tied to his wrist when he was killed. We did not find any other guns or weapons in his car, among his possessions or in any of the other locations we now know he visited in the hours leading up to the attack."
5. No drugs found in his system
Paulson addressed Zehaf-Bibeau's physical state the day of the attack, given that he admitted he had a drug addiction in court in 2011.
"I can confirm that the autopsy toxicology screen on Zehaf-Bibeau's remains was negative for drugs or alcohol. Neither did we uncover any evidence of drug and alcohol use by him in the period leading up to his attack.
"None of the intoxicants that we screen for were noted. They are typically alcohol, most of your common drugs, opiate-based stimulants, so it's limited by the scope of the [toxicology] screen."
Paulson also said no evidence of mental health issues has been uncovered.
6. RCMP shifts 600 people to counter threats
Paulson also addressed the amount of time and money the RCMP is putting into counter-terrorism.
"We have refined our practices in terms of priority management of some of these targets, but it is an unprecedented realignment of our resources to address that.
"Yes we have enough resources to deal with the threat we are facing … we're taking now a little over 600 resources from other areas of our federal responsibility to transfer those full-time equivalent positions into counter-terrorism work.
"We're shifting our federal resources, so things from organized crime cases, drug cases, financial integrity cases, the federal mandate.
"I am content to move resources around and address the greatest threat. I just don't think it's sustainable to maintain our programs in other areas when we're drawing resources from those to address this threat."