BOSTON - US President Barack Obama was due to visit Boston on Thursday to attend a memorial service for victims of the Boston Marathon bombing amid a manhunt for a suspect seen on video taken before two blasts struck near the finish line on Monday.
Obama will address an interfaith service and by extension the country following the blasts that killed three people and wounded 176 in the worst attack on US soil since Sept. 11, 2001.
The president also leaves a capital city that was abuzz on Wednesday after the US Federal Bureau of Investigation (FBI) arrested a Mississippi man in connection with letters sent to Obama and two other officials that were believed to have contained the deadly poison ricin.
The FBI said there was no indication of a connection between the ricin letters and the Boston bomb attacks, but they reminded Americans of anthrax mail attacks in the wake of the Sept. 11 suicide hijackings 12 years ago.
Investigators believe the Boston bombs were fashioned out of pressure cookers and packed with shrapnel. Ten victims lost limbs and emergency room doctors reported plucking nails and ball bearing from the wounded.