Police postpone news conference in Boston Marathon bombing
Investigators are still processing a very complex crime scene.
Krystle Campbell, 29, was killed in the attack.
People write condolences at one of several vigils.
Hundreds turned out for a Dorchester vigil to remember eight-year-old Richard Martin, who died in the attack.
Boston Police and the FBI says no arrest has been made in the Boston Marathon bombings, but Wednesday saw significant developments in the case.
A law enforcement official briefed on the investigation told The Associated Press on Wednesday a suspect was in custody, but the FBI and the U.S. attorney's office in Boston dispute that.
The official who spoke to The Associated Press did so on condition of anonymity and stood by the information even after it was disputed.
The official was not authorized to divulge details of the investigation. The official had said the suspect was expected in federal court in Boston.
Reporters and police have converged at the courthouse.
NBC News said in a special report at 2:00 pm that it could not confirm an arrest.
Police briefings scheduled for 5 p.m. and 8 p.m. were postponed.
This is a developing story that will be updated.
Meantime, CNN is reporting "substantial progress" in the investigation into the Boston Marathon attack.
The source CNN is quoting says officials believe they've spotted the bombing suspect on video provided by a nearby department store and from television news footage. The video shows the suspect placing a bag at the scene and then walking away, according to reports.
The suspect has not been identified publicly at this time.
As police begin the second full day of investigation into the terror attack at the Boston Marathon, people in that city and around the world are remembering the victims.
More than 170 were injured and three people were killed in the blasts. Wednesday morning, doctors at Boston Medical Center said two patients from the blast remained in critical condition and over a dozen other patients whose conditions were initially critical have been upgraded to serious or fair. Several people are recovering from amputations.
The bombs were pressure cookers packed with gunpowder, nails and ball bearings, likely carried in black nylon bags. Investigators have gotten thousands of tips, but they want more.
Tuesday, investigators took the unusual step of stopping travelers at Logan Airport to see if they have helpful pictures or videos.
"Someone knows who did this," said Richard Deslauriers, FBI.
The Boston area has seen an outpouring of sympathy and support for victims as investigators vow to get justice for them and this city.
In Dorchester Tuesday night, hundreds of supporters turned out for prayer and a candlelight vigil to remember eight-year-old Martin Richard, who died watching his father run the Boston Marathon. Martin's sister suffered a serious leg injury and his mother also had serious injuries.
Not far away, hundreds gathered on Boston Common trying to make sense of the senseless, together. They prayed for healing and honored the memories of the victims. Among those killed was 29-year old Krystle Campbell, whose mother spoke tearfully about her in front of their Medford home.
"Everybody that knew her loved her," said Patty Campbell.
The third victim killed in Monday's attack has been identified as a Boston University graduate student from China, but her name has not been released. She had gone to the finish line to watch the race with two of her friends.
As more than 70 recover in local hospitals from physical wounds, a city and nation slowly recovers from its emotional scars.