The camper van blast in Nashville on Christmas Day was probably a suicide bombing, law enforcement officials were quoted as saying by US media.
Investigators were conducting DNA tests after human remains were found near the site of the powerful blast.
The home of a possible person of interest was searched on Saturday in Nashville’s suburb of Antioch.
The blast injured three people and disrupted communications systems in Tennessee and four other states.
No motive has yet been established for the explosion in the state of Tennessee, and no-one has yet said they were behind it.
Meanwhile, businesses and TV personalities have offered more than $300,000 (£224,000) to catch those responsible.
Investigators believe that the blast was likely the result of a suicide bombing, according to two law enforcement sources cited by CNN.
CNN was also quoting an FBI official as saying that agents were not looking for another suspect after the human remains were found.
CBS News reported that the leading theory was that the subject may have been killed in the blast.
Newsweek reported that the investigators are trying to find the suspect’s mother to conduct DNA tests.
FBI Special Agent in Charge Douglas Korneski earlier said officials had received about 500 tips possibly relating to the explosion.
After visiting the site, Tennessee Governor Bill Lee said it was a “miracle” that no-one had been killed.
He said he had asked President Donald Trump for a federal emergency declaration for his state to aid relief efforts.
Source: BBC
