BOSTON - There are still no major leads in the Boston Marathon bombing investigation, but the president has called it an "act of terrorism."
A Saudi man, who was reportedly hospitalized under guard as a person of interest, has been cleared and released.
The death toll still stands at three Tuesday night, with 183 people injured, at least 17 critically.
The mother of 29-year-old victim Krystle Campbell spoke out Tuesday.
"We are heartbroken at the death of our daughter Krystle Marie. She was a wonderful person," Patty Campbell said.
Campbell said she can't believe that it happened.
"Everybody that knew her loved her. She loved her dogs, she was a dynamite girl, she had a heart of gold," Campbell said.
There has been progress Tuesday night to find the people who killed Campbell, 8-year-old Martin Richard and a Boston University grad student.
Teams discovered part of a circuit board from one of the bombs, pieces of metal which were propelled as a result of the explosions and nylon fragments believed to be from the duffel bag used to hide the bombs.
Two of the bombs went off 10 seconds apart near the finish line. The injured were treated for shrapnel wounds. Some ended up amputees.
Federal agents are reviewing surveillance video from cameras on Boylston Street. The president has come out and called this an act of terrorism against the U.S.
For one woman, it's an attack on her family.
"She was the best, you couldn't ask for a better daughter," Campbell said.
Tuesday night, there are still more than a dozen critically injured patients fighting for their lives.
President Barack Obama plans on heading to Boston on Thursday.
Mother of Boston Marathon bombing victim speaks out
Storms exit as tornado watches expire in Central Florida
Emergency operation centers open before severe weather hits Central Florida
Families of fallen Orlando police lieutenant, Orange County deputy to…
Blaze engulfs automotive warehouse near Oakland