When Michael Zehaf-Bibeau stormed through the front doors of Parliament brandishing a large rifle, was he executing a well-thought-out plan or acting on impulse? This is what investigators are trying to piece together in the aftermath of Wednesday's brazen attack in the capital.
In an interview Thursday morning, Ottawa Police Chief Charles Bordeleau said that moments after the shooter gunned down Corporal Nathan Cirillo at the War Memorial, Mr. Zehaf-Bibeau got in a car and made the short drive to Parliament Hill. At that point, he got out of the car and ran, witnesses said. The chief said that once "on the grounds" he hijacked a second vehicle and then drove to Centre Block.
Chief Bordeleau said police are now trying to determine how well Mr. Zehaf-Bibeau knew the area and building layout and whether he knew that the front door entrance had security weaknesses. That particular entry point, which is manned by a security officers, has no physical barriers, metal detectors or X-ray machines.
The chief would not say whether police are trying to find weeks-old local security footage to see if Mr. Zehaf-Bibeau had been in the vicinity recently.
The investigation is being led by the RCMP, although Ottawa officers are assisting with witness interviews, video analysis and crime scene management. The force's intelligence unit is also involved.
Around 9:50 a.m. Wednesday, police received numerous 911 calls about an attack on the Hill. Because of the different locations and speed between shootings, there was confusion about the number of individuals involved.
Throughout the afternoon, police refused to say whether they were looking for other gunman. Large swaths of the downtown remained closed off. MPs who spent the day in lockdown weren't released until after 9 p.m.
Police confirmed on Thursday that Zehaf-Bibeau was the only gunman involved.
"As you can appreciate the investigation was fluid and dynamic… we were receiving conflicting accounts of what people were seeing. Until we were able to absolutely refute the fact there's a second shooter, our primary goal is public safety," said Chief Bordeleau.
Officers conducted a room-by-room search of the Hill, reviewed surveillance footage and interviewed witnesses. It wasn't until 7 p.m. Wednesday that police felt confident Mr. Zehaf-Bibeau was the only shooter.
"There was only one subject directly involved in the shooting at the War Memorial and Parliament Hill," the chief confirmed Thursday. He would not say whether police have any leads on individuals who may have indirect involvement. "That's part of the investigation."
A spokesperson with the Vancouver Police Department confirmed they are also co-ordinating with the RCMP and Ottawa force. Mr. Zehaf-Bibeau lived in that city recently.