Diane Sawyer to Anchor a Special Expanded One-Hour Edition of "ABC World News"

ABC News to Air a Special Edition of "Nightline" with Terry Moran Anchoring From Boston

ABC News continues to provide comprehensive coverage of the events and investigation following yesterday's explosions at the Boston Marathon. ABC News has a team of correspondents and anchors reporting from Boston including "Nightline" Anchor Terry Moran, "GMA" News Anchor Josh Elliott, Chief Investigative Correspondent Brian Ross, "GMA" Weekend Anchor Dan Harris, and Linsey Davis.

All ABC News broadcasts and platforms are delivering the latest updates on the ongoing investigation as well as the stories of those who witnessed the tragic attack -

• " World News with Diane Sawyer" will have the latest on the investigation during a special one-hour editionof the broadcast which will include reports from ABC's team in Boston as well as Chief National Correspondent Byron Pitts, Chief Global Affairs Correspondent Martha Raddatz, Chief White House Correspondent Jonathan Karl, Senior Justice Correspondent Pierre Thomas, and Senior National Correspondent Jim Avila. - UPDATE: Diane Sawyer will speak to Dr. Dave King, a trauma surgeon at Mass General in Boston. In addition Boston Mayor Thomas Menino and former New York City Mayor Rudy Giulini will speak with Sawyer.
• " Nightline" will originate from Boston with Terry Moran anchoring from there. The program will feature reports by Brian Ross and John Donvan.
• ABCNews.com has live updates here: http://abcn.ws/13hHWlm. ABC News is also live-streaming coverage as news warrants at abcnews.go.com/live.
• ABC News Radio Correspondent Aaron Katersky is reporting from Boston.
• ABC NewsOne Correspondents Marci Gonzalez and Tahman Bradley are reporting from Boston for nearly 200 ABC affiliates, stations and clients.

On Monday, two small but powerful bombs exploded at the finish line of the Boston Marathon and 24 hours later no one has claimed responsibility for what authorities have labeled a "terrorist" attack. FBI says investigation will be worldwide. "We will go to the ends of the earth to find subject or subjects responsible for this despicable crime," said FBI Special Agent in Charge Richard DesLauriers.

For the latest information on ABC's coverage of this story click here.