Lawmakers are asking tough questions about how the government tracked suspected Boston Marathon bomber Tamerlan Tsarnaev when he traveled to Russia last year, renewing criticism from after the Sept. 11 attacks that failure to share intelligence may have contributed to last week’s deadly assault.

• A man accused of plotting with al-Qaida members in Iran to derail a train in Canada was due to appear in a Toronto court Wednesday after declaring at his initial court appearance that the charges against him are unfair. Law enforcement officials in the U.S. said the target was a train that runs between New York City and Canada.

Charges were dropped Tuesday against the Mississippi man suspected of mailing ricin-laced letters to President Obama and other public officials — as authorities searched the home of another man hoping to find clues in the expanding investigation.

• On Tuesday, hackers took over the Associated Press Twitter account and falsely claimed that there had been explosions at the White House and that the president was hurt. The tweet was up for a few minutes before Twitter took the account offline.

The Justice Department late Tuesday formally filed its case against Lance Armstrong and his company Tailwind Sports for millions of dollars that the U.S. Postal Service spent to sponsor the cycling team.