Police were able to piece together the events that transpired at the National War Memorial through first-hand accounts from several witnesses, Paulson said during a news conference in Ottawa on Thursday.
The suspect was caught on video once he was in his car driving along Wellington St. up to Parliament Hill. From there, a number of security cameras captured the suspect from various angles making his way up to Centre Block.
It was "a fluid and dangerous situation," Paulson said.
Here is a timeline of events:
9:50:00 a.m. Witnesses report seeing the gunman coming from behind the National War Memorial, on the west side where he fired twice at Cpl. Nathan Cirillo. The shooter also fired one shot at the second reservist guarding the Tomb of the Unknown Soldier but missed.
Paulson said witnesses heard the suspect "yelling something" in English before running north. What he said is not known. The suspect uses a beige-coloured vehicle to make his way to Parliament.
9:52:23 a.m. From the National War Memorial, the suspect is seen on camera driving his car on Wellington Street and parking it at the Elgin Street entrance of Parliament Hill.
9:52:31 a.m. Here the suspect is seen accessing the grounds on foot. He gets out of his car carrying a weapon and running through the security posts and up towards the east block where MPs' cars are parked.
A handful of people are seen running away from him. This moment is captured by at least three different security cameras, each providing a different view.
9:52:36 a.m. Paulson said this is when the first 911 calls were made.
9:52:40 a.m. The suspect is seen running on the grass towards three cars parked along the East Block.
9:52:50 a.m. The gunman runs towards the first of three cars which is occupied by a driver. The suspect goes around to the front of the car to the driver's side. There is an exchange with the driver, who then gets out of the car and runs away.
9:53:16 a.m. The suspect hijacks the ministerial car and drives off from the East Block towards Parliament's Centre Block.
9:53:23 a.m. "It's at this point that those actions were noticed by RCMP officers," Paulson said. An RCMP vehicle, with the driver's door opened, is seen in pursuit of the suspect.
9:53:36 a.m. A second RCMP car is also in pursuit.
9:53:37 a.m. The suspect's car comes to a stop on the left side of the Peace Tower. He gets out of his car and runs towards the front doors of Centre Block.
9:53:43 a.m. Police officers pursue the suspect to the door.
9:53:46 a.m. The suspect enters Centre Block seconds before the RCMP officers who were chasing him reach the main entrance doors.
It took little more than one minute for the suspect to go from Wellington to Centre Block. "It was incredibly quick," Paulson said.
9:53:57 a.m. A third RCMP vehicle arrives at the entrance of Parliament.
"Once inside Centre Block, the suspect engaged in a fire exchange with House of Commons security and RCMP officers," Paulson said.
The exact details of this dramatic "fire exchange" are still under investigation.
The suspect, later identified as Michael Zehaf-Bibeau, was pronounced dead at the scene.