Top-Ranking GOP Rep. Says There Are 'Clearly More Persons of Interest' in Boston Bombing

Law enforcement investigators work near the finish line of the Boston Marathon on April 21, 2013. (Getty Images)

The chairman of the House Intelligence Committee said there are "clearly more persons of interest" in the Boston Marathon bombing, despite some officials saying the Tsarnaev brothers acted alone.

“I hear a lot of definitive statements out there that it was just these two men and it’s over, but I will tell you I hear these briefings every day, and I don’t think this is over,” Rep. Mike Rogers (R-Mich.) told The Boston Herald Thursday. “There are clearly more persons of interest, and they’re not 100 percent sure if there aren’t other explosives.”

Rogers' comments came ahead of a Wall Street Journal report Friday that the FBI has concluded the bomb makers "likely had additional training or expertise."

Captured bombing suspect Dzhokhar Tsarnaev reportedly told investigators he and brother Tamerlan made the devices using instructions from the Al-Qaeda magazine "Inspire." Tamerlan Tsarnaev died last week after a gun battle with police.

"The FBI's bomb experts analyzed remnants of both bombs that exploded on April 15 near the marathon's finish line...[t]heir early conclusion is that the bomb makers likely had additional training or expertise, in part because they deviated from two recipes in Inspire," the Journal reported.

Additionally, Fox News reported Friday that investigators believe the bombs were set off using a "line of sight" controller, not a cell phone detonator. Such a controller would typically have a range of 250 yards or less, and as such, investigators have not ruled out that a third person was involved in the attack, according to Fox.