First a soldier guarding a hallowed war memorial was gunned down in Canada's capital. Then shots erupted in the halls of the country's Parliament minutes later.
The two shootings in Ottawa Wednesday left lawmakers barricaded inside offices and parts of the city on lockdown for hours as police searched for suspects.
Ottawa Police lifted the lockdown Wednesday night and said there was no longer a danger to the public.
But many questions remain about the shootings: Who was the gunman? Why did he open fire? And was he acting alone?
"It appears there was just one shooter, and that shooter is dead," Ottawa Mayor Jim Watson told CNN's Anderson Cooper. "But it has been a traumatic experience, obviously, for not only our city but the country."
Investigators haven't provided any possible motives for the shooting. Canadian Prime Minister Stephen Harper didn't provide details about the investigation in a televised address to the nation Wednesday night.
"In the days to come, we will learn more about the terrorist and any accomplices he may have had, but this week's events are a grim reminder that Canada is not immune to the types of terrorist attacks we have seen elsewhere in the world," Harper said. "Let there be no misunderstanding: We will not be intimidated. Canada will never be intimidated."
It is unclear whether additional suspects were tied to the shootings or whether additional arrests have been made. The Royal Canadian Mounted Police said more information would be provided in a press conference Thursday.
As authorities continued to investigate, details began to emerge about the man they suspect was behind the shooting.
Michael Zehaf-Bibeau was identified by Canadian officials to their American counterparts as the suspected gunman, multiple U.S. officials told CNN.
Bibeau, who was born in 1982, was a convert to Islam and had a history of drug use before he converted, two sources said.
His passport had been confiscated by Canadian authorities when they learned he planned to go fight overseas, a U.S. law enforcement official told CNN's Susan Candiotti. The official said it was not clear when that happened.
Canadian broadcaster CBC reported that Bibeau had a record of drug arrests going back 10 years.
See more on this developing story on CNN.com
U.S. airstrikes "are not going to save" the key Syrian city of Kobani from being overtaken by ISIS, said Pentagon spokesman Rear Adm. John Kirby.
"I think we all should be steeling ourselves for that eventuality," he told reporters in a daily briefing Wednesday.
"We are doing everything we can to halt" ISIS' progress against the town, but airstrikes alone cannot stop the Islamist militants, Kirby added.
"We've been very honest about the limits of air power here. The ground forces that matter the most are indigenous ground forces, and we don't have a willing, capable, effective partner on the ground inside Syria right now - it's just a fact," he said.
The greater U.S. strategy, Kirby said, is to degrade ISIS' ability to sustain itself.
Several senior U.S. administration officials said Kobani will soon fall to ISIS, which calls itself the Islamic State.
They downplayed the importance of it, saying the city is not a major U.S. concern.
But a look at the city shows why it would mark an important strategic victory for the militants. ISIS would control a complete swath of land between its self-declared capital of Raqqa, Syria, and Turkey - a stretch of more than 100 kilometers (62 miles).
As Time.com put it, "If the ISIS militants take control of Kobani, they will have a huge strategic corridor along the Turkish border, linking with the terrorist group's positions in Aleppo to the west and Raqqa to the east."
Staffan de Mistura, U.N. special envoy for Syria, warned of the horrors ISIS could carry out against the people of Kobani - horrors it has carried out elsewhere. "The international community needs to defend them," he said. "The international community cannot sustain another city falling under ISIS."
The terrorist group claimed it had downed at Iraqi army helicopter in Baiji. Photographs posted to an ISIS website show smoke and fire around an aircraft, which is then seen completely charred on the ground.
A truck bomb driven by ISIS exploded near the center of Kobani. Two civilians and a fighter inside the city described it as huge. The target was a security forces building, they said.
However, Kurdish official Idriss Nassan told CNN, the truck did not reach its intended target and detonated early.
See more on this developing story on CNN.com.
A nurse's assistant in Spain is the first person known to have contracted Ebola outside of Africa in the current outbreak.
Spanish Health Minister Ana Mato announced Monday that a test confirmed the assistant has the virus.
The woman helped treat a Spanish missionary and a Spanish priest, both of whom had contracted Ebola in West Africa. Both died after returning to Spain.
Health officials said she developed symptoms on September 30. She was not hospitalized until this week. Her only symptom was a fever.
See more on this developing story on CNN.com
A nurse in Nigeria. A businessman in Saudi Arabia. A Spanish priest in Liberia.
With the World Health Organization announcing Wednesday that 932 deaths had been reported or confirmed as a result of Ebola hemorrhagic fever, Saudi Arabia joined the list of countries with suspected cases.
"This is the biggest and most complex Ebola outbreak in history," Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, said.
Nearly all of those deaths have been in Liberia, Sierra Leone and Guinea, where more than 1,700 cases have been reported, according to WHO. The agency said 108 new cases were reported between Saturday and Monday in those countries and Nigeria.
Liberian President Ellen Johnson Sirleaf has declared a state of emergency for 90 days because of the deadly outbreak, her office announced Wednesday.
"The scope and scale of the epidemic, the virulence and deadliness of the virus now exceed the capacity and statutory responsibility of any one government agency or ministry," she said in a written statement. "The government and people of Liberia require extraordinary measures for the very survival of our state and for the protection of the lives of our people."
She said Ebola is a "clear and present danger."
Concerns about the spread of the deadly virus escalated with Saudi Arabia reporting that a man died, apparently of the virus, after a trip to Sierra Leone, and Nigeria reported that a nurse died after treating someone believed to have contracted Ebola in Liberia.
WHO did not immediately confirm the deaths, and its count of Ebola cases does not include the two.
The Saudi man died Wednesday at a specialized hospital in Jeddah, the Saudi Ministry of Health said.
He had been in intensive care since late Monday "after exhibiting symptoms of viral hemorrhagic fever following a business trip to Sierra Leone," the ministry said in a statement.
The nurse in Nigeria had helped care for Patrick Sawyer, a Liberian-American man, who died in Nigeria after traveling there from Liberia, Nigeria's Ministry of Health said Wednesday.
See more on this developing story on CNN.com
While the vast majority of casualties are Palestinians in Gaza, Israel continues to ward off rocket attacks from Gaza with its Iron Dome missile defense system. Israeli officials say they are committed to destroying tunnels used by Palestinian militants in Gaza to make their way into Israel.
A poll released this week showed 86.5% of Jewish Israelis surveyed say Israel cannot accept a cease-fire because "Hamas continues firing missiles on Israel, not all the tunnels have been found, and Hamas has not surrendered," according to the Jerusalem Post.
But Israel's incursion into Gaza has had ripple effects around the world. Chile, Peru, Brazil and Ecuador have pulled their ambassadors out of Tel Aviv to protest the Israeli offensive.
It's unclear how many in Gaza want militants to stop rocket attacks.
Last month, a poll by the Washington Institute for Near East policy found most Palestinians in Gaza oppose a two-state solution and want to work toward a five-year goal of abolishing Israel. But the majority said they support nonviolent methods of "popular resistance."
Most Israelis support a two-state solution, according to a poll by the Dialog Institute, Haaretz reported.
See the latest on this story on CNN.com
A second case of the potentially deadly MERS virus has been identified in the Netherlands, a spokeswoman for the country's National Public Health Institute told CNN. It comes one day after authorities confirmed the first case.
The cases in the Netherlands involve two family members who had traveled together to Saudi Arabia.
It is one man and one woman who contracted the disease, said Harald Wychgel, spokesman for the Netherlands ministry of health.
The health ministry, citing privacy reasons, did not provide additional details except to say that the pair shared a room for two weeks in Saudi Arabia.
Officials do not know if one person infected the other or if both became infected at the same location. One of the two, however, had visited a camel farm. It is estimated that nearly 75% of dromedary - or single-hump camels - in Saudi Arabia have come into contact with the MERS virus, researchers said in February.
"It is also known that both patients have underlying conditions that make them probably more susceptible to infection with this virus," the health ministry said in a statement.
The announcement comes as the World Health Organization said the spread of the virus has become more urgent, but at least for now, is not calling it a global health emergency.
The first cases of Middle East Respiratory Syndrome were diagnosed in the Arabian Peninsula in 2012. MERS attacks the respiratory system, and symptoms can lead to pneumonia or kidney failure.
There have been over 570 confirmed cases of MERS, including 171 deaths, according to the World Health Organization.
Many of the cases are in Saudi Arabia and the United Arab Emirates.
Even without any official worldwide alert, Anne Schuchat, the head of the CDC's National Center for Immunization and Respiratory Diseases, acknowledges that "this is a relatively new virus that does have a high fatality rate," ample reason to pay attention. Authorities haven't pinned down all the details about how exactly it arose and how it spreads, though Schuchat said, "We don't have evidence right now that this is airborne ... the way the measles virus is."
Two cases have been confirmed in the United States. Both patients are health care providers who were working in Saudi Arabia. Those cases are in Indiana and Florida.