Friday morning America woke up to more mayhem — a manhunt for a terror suspect in suburban Boston. The whole city on lockdown. One suspect dead. Officer slain. Another officer shot. Thousands of officers geared up and ready for battle.

It was utterly captivating. It was also almost unendurable, even at a distance, far from Boston. A person would be forgiven for turning off the television, shutting down the computer and going back to bed to hide under the covers. For those of a gentle disposition, this was all too much like an episode of “24” or a Bruce Willis movie.

This was one of the most chaotic and unnerving weeks in years. There was a relentless nature to the bad news, and a randomness. Like: An Elvis impersonator allegedly mailed poison-laced letters to the president and a senator (many people have sagely noted that Elvis would never do a thing like that).

Then came the catastrophic explosion at a fertilizer storage facility in West, Tex., which killed more than a dozen people and leveled much of the town. That would have been the dominant national story for days on end but for what unfolded Friday in Boston.

At first only the suburbs went on lockdown, but then everyone in the region was told to shelter in place. This was unprecedented. What made the situation all the more disturbing was the mystery at its core: The suspected terrorist, a mere teenager, had vanished in the night, and could have been anywhere. Watertown? Cambridge? On a train to New York City? Conflicting news reports did little to settle the nerves in Boston.

President Obama spoke in rememberance of the three victims of the Boston Marathon bombing and praised the resilience of the city of Boston at an interfaith service on Thursday. (The Washington Post)

The motive for the marathon bombings is still unknown. The two brothers named as suspects, Tamerlan (killed) and Dzhokhar Tsarnaev (in custody Friday evening), are Chechens, reportedly raised in Kyrgyzstan — everyone go to Google Maps. But they have been in this country for many years.

It may be a while before this story coheres into something we can understand. It may involve a confluence of the kind of terror narratives and criminal patterns we’ve seen in recent years, including radical ideology, anti-Americanism, overseas indoctrination, alienated youth, divided families, a strong-willed older figure and a pliant younger one (shades of the Washington sniper attacks), and finally the desire to do something spectacular with maximum media exposure.

The bombers were able to kill innocent people with makeshift bombs using ordinary pressure cookers and material that might have cost only $100. Thursday night, according to law enforcement authorities, they killed an MIT campus police officer, carjacked a Mercedes SUV and tried to flee. The details are still emerging and are subject to revision, but pending further information, these do not appear to be a couple of criminal masterminds.

A striking feature of this week’s news has been misinformation. That’s been a problem with every huge, breaking news story, including 9/11 (Washingtonians, for example, heard incorrect reports of explosions at the State Department, the Capitol and the USA Today building). But the rise of social media has sped up the misinformation metabolism. The social-media search for the Boston bombers this week failed to identify the suspects and revealed the pitfalls of a crowdsourced investigation.

Worse, reputable news organizations embarrassed themselves by reporting an arrest when none had been made. The New York Post set a standard for journalistic inauspiciousness when it put two innocent guys on the front page after their picture had been circulated by authorities. The executive editor later defended the decision by saying that the paper never called them suspects.

So this week has been a learning experience. Lesson one: Be skeptical, because sometimes facts will evaporate in sunlight.

National tragedies are rarely so prolonged, so unbounded. We come to expect that, after the horror, there will be a period of mourning, an attempt at closure, perhaps a church service with remarks by the president in his role of Consoler in Chief.

But this has been the story that didn’t want to end, that kept finding new twists, and until Friday night, the great American city of Boston was essentially held hostage by a single 19-year-old who had vanished overnight.

Finally, about 8:45 p.m., the cornered suspect was taken into custody — cheers and high-fives from the cops who had surrounded him — and Bostonians could exhale, retake their city and celebrate their freedom from fear.

The third week in April has been cruel to our country in recent years. The Branch Davidian fire (1993), Oklahoma City (1995), Columbine (1999), Virginia Tech (2007), the BP oil spill (2010) and now the Boston Marathon bombing all took place between April 15 and 20. For that matter, the Texas City fertilizer explosion of 1947, America’s worst industrial accident and the precursor to what happened this week, occurred on April 16. Keep going back in time and there are more calamities, including the Titanic and Lincoln’s assassination.

The Oklahoma City bombing was timed to be on the anniversary of Waco, but otherwise these unhappy Aprils are a coincidence — a fluke of the calendar that Americans can hope and pray will be forgotten amid many peaceful and beautiful Aprils to come.