5 stories to follow: April 17

A U.S. Capitol Police hazmat vehicle is parked at a mail processing facility for Congressional mail in Prince George's County where a letter addressed to Sen. Roger Wicker, R-Miss., tested positive for ricin, Tuesday, April 16, 2013. (AP photo)

Here are five stories we have on our radar today:

1. Boston bombings: Investigators are continuing to search for answers after Monday's bombings at the Boston Marathon, and details about the victims are becoming known. One severely injured man, whose photo has become one of the iconic images of the disaster, has deep roots in Philly and South Jersey. More coverage: The scene in Boston on Tuesday, why race security is hard to guarantee, how to help, a Temple doctor's story.

2. Ricin letter: A letter sent to Mississippi Sen. Roger Wicker is believed to have contained ricin, a potentially deadly poison. Further tests are being done, and fellow Sen. Claire McCaskill says a suspect has been identified.

3. Library merger: The Free Library of Philadelphia Foundation and Rosenbach Museum Library are working on a merger. Details still need to be negotiated, but current plans call for the Rosenbach to become a subsidiary of the Free Library by the end of June. 

4. Gosnell trial: The murder trial for the West Philadelphia abortion doctor is in its fifth week, and the jury heard Tuesday about the death of a 41-year-old woman at his clinic. After much online coverage of the lack-of-coverage by the national press, more reporters from news outlets outside of Philadelphia covered the trial this week. Karen Heller argues that critics of the press made the trial a political story, no longer about the victims.

5. Thatcher funeral: Former British Prime Minister Margaret Thatcher's funeral, an event with full military honors, will take place today at St. Paul's Cathedral in London.