According to livescience.com, reporter Tom Llamas told Matt Lauer that "over the last 20 years in this country, several terrorist attacks and school shootings have taken place around this time of the year."
This seems to be a trend in American history, with even the American Revolutionary War beginning in April.
Here are some deadly and violent events that have happened on April 19 or April 20 according to Wikipedia.
April 19
In 1775, the British government and the American colonies hit a breaking point and the American Revolutionary War began. The first battles fought were the battles of Lexington and Concord, which would turn a colonial uprising into a world war before finally, seven years later, created the independent United States of America.
In 1989, there was an explosion aboard the USS Iowa in the Caribbean off Puerto Rico. The blast, which came from the center gun room, killed 47 sailors. There was a lot of speculation as to what actually happened. One theory from the Navy was that a crew member had suicidal tendencies and sparked the blast, but later said there was a lack of proof on that theory.
In 1993, a 51-day siege (Feb. 28-April 19) ended in flames when federal agents came smashing into the Branch Davidian compound near Waco, Texas. A fire engulfed and destroyed the structure, killing 76 Branch Davidians.
In 1995, a truck bomb set off by Timothy McVeigh and Terry Nichols went off in Oklahoma City. This domestic terrorist attack killed 168 people, injured 680 others, destroyed and damaged 324 buildings including the Alfred P. Murrah Federal Building, and caused an estimated $652 million in damages.
April 20
In 1889, the main person responsible for the deaths of at least 11 million people was born, Adolf Hitler. He was born in Braunau am Inn, Austria. Hitler was at the center of Nazi Germany, World War II in Europe, and the Holocaust.
In 1914, the Ludlow Massacre was an attack by the Colorado National Guard on a colony of striking miners and their families. While accounts vary, about two dozen people, including strikers, women and children died.
In 1999, two Colorado students, Eric Harris and Dylan Klebold, opened fire at their high school, killing 12 of their classmates and one teacher, injuring 21 others, and finally, taking their own lives. The motives for the two involved in the Columbine High School massacre remain unclear.
In 2010, an explosion and subsequent fire took place on the Deepwater Horizon oil platform, which was owned and operated by Transocean and drilling for BP. This accident killed 11 workers and caused a blow-out that polluted the Gulf of Mexico with an estimated 200 million gallons of crude. It took nearly 3 months to stop the spill.
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