Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
President Obama announces U.S. troops and funds will be sent to help fight Ebola.
In the wake of tragedy, come the inevitable questions: What makes a killer? Is there a switch that turns on a rampage? And why, why, did they do it?
"You can just say the person's evil," said Adrian Raine, criminologist and the author of a new book "The Anatomy of Violence." "I think that's 13th century thinking. I think we've moved beyond that."
Raine has spent more than three decades studying cold-blooded killers. He says there are biological explanations for violence. Raine is convinced that brain dysfunction may – in part – explain the terror unleashed in Boston.
"Were they completely normal people ... who just decided one day, 'You know what, we want to create mayhem?'" said Raine. "I don't think so. I think it's more complicated than that."
President Obama announced Thursday that Penny Pritzker, an ex-national finance chair for the Obama campaign, will lead the Commerce Department. If confirmed, she will be the richest cabinet secretary in U.S. history. The president already skipped over her for the nod once.
The New York Times said of Pritzker in 2008, "Ms. Pritzker's family is renowned for finding ways to avoid paying taxes on its wealth. The Pritzkers were pioneers in using tax loopholes to shelter their holdings from the internal revenue service, and many of their dealings have never been made public."
The man who put American jihadi John Walker Lindh behind bars told CNN's Jake Tapper Thursday Dzhokhar Tsarnaev still has to worry about receiving the United States' harshest sentence for criminals: the death penalty.
"I don't know that it will be taken off the table," David Kelley said.
The former prosecutor said two things will factor in to the federal attorneys trying the younger Tsarnaev, charged with using a weapon of mass destruction and killing three people when he and his brother, Tamerlan, exploded pressure cooker bombs near the finish line of the Boston Marathon, decide to seek the death penalty. First, Kelley said, prosecutors will evaluate Tsarnaev's cooperation with the investigation.
The other factor – and the more difficult one to determine – is how much Dzhokhar was influenced by his brother, the alleged mastermind of the double bombing. Kelley asserted that the prosecutors' decision to seek the death penalty could hinge on the extent to which they feel Dzhokhar was drawn into the plot through the influence of Tamerlan, who, according to Kelley, "seems to be the key, main actor."
Over a decade after the worst terrorist attack in our nation's history, it seems that the U.S. immigration system that allowed the September 11 hijackers to enter the country legally is still flawed.
Some lawmakers question whether Boston bombing suspect Tamerlan Tsarnaev should have been so easily admitted back into the U.S. after his trip to Russia, Chechnya, and Dagestan last year. After all, in 2011 the Russian government warned both the FBI and the CIA that they were worried that Tsarnaev had become an extremist, and would be traveling to meet with underground groups. The U.S. investigated and found nothing.
Now there is another concern. Three friends of alleged bomber Dzhokhar Tsarnaev have now been arrested for their alleged involvement after the Boston Marathon attack. Azamat Tazhayakov, Dias Kadyrbayev, and Robel Phillipos all went to school with Tsarnaev at the University of Massachusetts Dartmouth. Two are accused of removing evidence from Tsarnaev's dorm room after the attack, including a backpack containing fireworks and a laptop.
One of Dzhokhar Tsarnaev's three friends Azamat Tazhayakov, of Kazakhstan, should not have been allowed in the country at all. Tazhayakov is currently charged with obstruction of justice.
He was staying in the U.S. on a student visa, but is no longer a student. Tazhayakov returned to Kazakhstan in December 2012, according to a U.S. government official. While he was overseas, the University of Massachusetts Dartmouth terminated his status as a student, on January 4.
At that point, his student visa should have been invalidated. The university took the proper steps, and provided information to the appropriate system for foreign students, flagging that he was no longer registered.
But Customs and Border Protection never got the message, so when he returned to the states on January 20, CBP granted Tazhayakov entry.
Resources and funding are a big issue.
"The government has information in their systems but they don't talk to each other, and Congress has not funded them sufficiently to do that," said Julie Myers Wood, former director of Immigration and Customs Enforcement (ICE). Wood is now president of Guidepost Solutions.
Moreover, continued Wood, law enforcement officials are also insufficiently funded.
For the approximately 850,000 foreign students that pass through the U.S. visa system last year, "you know how many investigations ICE opened up into visa overstays, all the overstays, not just students?" asked Wood. "About 3,000, and only made 123 criminal arrests."
Wood said that in Tazhayakov's case, not enough time had passed between the university terminating his status and his re-entry.
"The I.T. systems don't share this information automatically," said Wood.