No suspects have publicly emerged in the probe into Monday’s bombing of the Boston Marathon. The two bombs were probably built from six-liter pressure cookers, filled with nails and small ball bearings. FBI Special Agent Richard DesLauriers said the explosives may have been carried to the scene in black nylon bags.

FBI Special Agent Richard DesLauriers: “Among items partially recovered are pieces of black nylon, which could be from a backpack, and what appear to be fragments of BBs and nails possibly contained in a pressure cooker device. We are expediting this blast evidence to our laboratory in Quantico, Virginia, for a complete and thorough analysis. In addition, this morning it was determined that both of the explosives were placed in a dark-colored nylon bag or backpack. The bag would have been heavy because of the components believed to be in it. We are asking anyone who may have heard someone speak about the marathon or the date of April 15th in any way that indicated that he or she may target the event to call us. Someone knows who did this.”

According to The Boston Globe, 70 victims remained in area hospitals overnight, including 24 in critical condition. The death toll stands at three. The second fatality was identified on Tuesday as 29-year-old Krystle Campbell, a restaurant worker from Medford. Her mother, Patty Campbell, broke down in tears as she spoke to reporters.

Patty Campbell: “We are heartbroken at the death of our daughter Krystle Marie. She was a wonderful person. Everybody that knew her loved her. She loved her dogs. She used to … She had a heart of gold. She was always smiling from — you could not ask for a better daughter. I can’t believe this has happened. She was such a hard worker in everything she did. This doesn’t make any sense.”

The third casualty was also identified Tuesday as Lu Lingzi, a Chinese national attending graduate school at Boston University.

Hundreds of people turned out for a pair of vigils Tuesday night honoring the victims. In Dorchester, mourners paid tribute to the first confirmed death, eight-year-old Martin Richard. On Tuesday, a photo was published online showing Martin Richard holding a handmade sign that read “No more hurting people. Peace.” Meanwhile, hundreds more gathered on the Boston Common.

Lucas Donahue: “It’s been bizarre seeing the Commons with National Guard troops on one side and peace here and everywhere in front of us. And it’s just — it’s, I guess, a juxtaposition of the two things, but it’s incredibly sad and also hopeful.”

Adel Aghel: “We’ll be stronger next marathon next year, and we’ll be like, you know, in a better shape. They are not going to — they are not going to win; they’re going to lose, no matter what. No matter how they do it, they’re going to lose, and that’s what’s going to happen. So — and you can see it right here.”

President Obama will travel to Boston for a memorial on Thursday. At the White House, Obama called the bombings an “act of terror.”

President Obama: “This was a heinous and cowardly act. And given what we now know about what took place, the FBI is investigating it as an act of terrorism. Any time bombs are used to target innocent civilians, it is an act of terror. What we don’t yet know, however, is who carried out this attack or why, whether it was planned and executed by a terrorist organization, foreign or domestic, or was the act of a malevolent individual. That’s what we don’t yet know.”

Federal investigators have confirmed a wounded Saudi national initially held as a “person of interest” is a victim of the attack, not a suspect. The victim was placed under police guard after suffering serious wounds at the scene of the bombing and subsequently questioned. Police later searched his home.

At least five people have been killed in a U.S. drone strike in Pakistan. Unidentified Pakistani government officials say the attack destroyed a Taliban training compound in the South Waziristan tribal region.

Venezuela’s political divide continues to worsen days after voters elected Nicolás Maduro to serve out the remainder of Hugo Chávez’s term. Venezuela’s National Electoral Council has ruled out a recount after certifying Maduro defeated opposition leader Henrique Capriles by about 275,000 votes. But Capriles has refused to recognize Maduro’s victory and is demanding a new tally of all ballots. Seven Maduro supporters were killed and dozens injured in post-election clashes on Monday. Both sides have accused the other of stoking unrest. On Tuesday, President-elect Maduro accused the opposition of planning a coup. He also said the United States is trying to destabilize Venezuela after the U.S. State Department said it backed calls for a full recount.

Federal authorities have intercepted a letter containing poison sent to Republican Sen. Roger Wicker of Mississippi. Preliminary tests show the letter contained ricin. It was posted from Memphis with no return address. All Capitol Hill mail has undergone heightened screening following the anthrax attacks in the aftermath of 9/11.

Senate leaders have agreed to hold votes in the coming days on a number of key amendments to an overall package on gun control. The measures include a ban on assault weapons and high-capacity magazines. It is widely known that proposal lacks enough support, with a number of Democrats joining Republicans in opposition. The Washington Post now reports a highly touted compromise on background checks is also short of the needed votes. The Manchin-Toomey amendment would expand background checks to all commercial gun sales, but exclude gifts and transfers between relatives. But according to the latest tally, only 52 senators have signed on to the measure, eight short of the 60-vote threshold. Eight senators remain undecided.

The American Civil Liberties Union and Center for Reproductive Rights have filed a lawsuit challenging an Arkansas law banning abortion at 12 weeks of pregnancy. The ban is scheduled to to take effect in mid-July. Rita Sklar, head of the ACLU of Arkansas, called it “one of the most dangerous assaults on women’s health that we’ve seen in decades.” When it passed last month, the 12-week ban was the strictest in the country, but it was soon surpassed by North Dakota’s ban on abortion at around six weeks of pregnancy.

An Ohio man has been sentenced to 20 years in prison for trying to destroy a local mosque. Randolph Linn set fire to a prayer rug in the Islamic Center of Greater Toledo in September. He had packed his car with a number of firearms and three cans of gas.

A coalition of environmental groups is accusing the State Department of critical errors in a review that concluded the Keystone XL pipeline does not threaten the global climate. Released last month, the long-awaited assessment said tar sands oil would increase emissions between 5 to 19 percent, not the far greater numbers critics have alleged. The State Department review marked a major boost to the Keystone XL pipeline’s chances as President Obama mulls whether to approve or reject it. But in a new report, Oil Change International, Sierra Club, Natural Resources Defense Council, 350.org and Friends of the Earth say the State Department review takes for granted the oil industry’s argument that increased future oil production is inevitable. The report, called “Cooking the Books,” concludes: “In a world constrained by the realities of climate change, the proper measure of any project’s climate impact should not be based on the assumptions inherent in a business as usual scenario that guarantees climate disaster. … There is a climate impact from burning 830,000 barrels per day of any crude that cannot be ignored.”

New figures from the United Nations show malnutrition has permanently stunted the physical and intellectual health of more than a quarter of children under the age of five across the globe. Unveiling the findings, Werner Schultink, the chief of nutrition at the United Nations Children’s Fund, said addressing child malnutrition is critical to tackling global poverty.

Werner Schultink: “If we want to achieve a world where there is better equity, where there is less poverty, and that we’re able to reduce poverty levels in a sustained manner, we need to put people on the right track in life. And the most fundamental thing to do that is by ensuring that there is good nutrition in the period of pregnancy and two years of age. If you want to tackle poverty, you need to tackle stunting.”

New Zealand lawmakers have voted to legalize same-sex marriage in a 77-to-44 vote. New Zealand becomes the 13th country to recognize same-sex marriage and the first in the Asia-Pacific region.