Boston, Apr 17 (EFE).- Investigators are making slow progress in identifying those behind the bombings at the Boston Marathon, with a pressure cooker used to carry out the attack providing one of the strongest leads.
Specialists are reconstructing evidence gathered at the crime scene near the finish line of the most famous road race in the United States, but investigators still have no evidence indicating whether domestic or foreign terrorists were involved.
At least one of the bombs that exploded Monday near the race's finish line and possibly both were made from an explosive charge packed into a pressure cooker, officials said.
Pressure-cooker bombs are simple to make and commonly used by both Islamic terrorists and domestic terrorists.
The pressure cooker containing the explosives may have been carried to the targeted location in a backpack or black nylon bag, officials said.
The two bomb blasts at the finish line of the Boston Marathon killed three people and wounded 176 others, 17 of them critically.
"This was a heinous and cowardly act. And given what we now know about what took place, the FBI is investigating it as an act of terrorism. Anytime bombs are used to target innocent civilians it is an act of terror," President Barack Obama said Tuesday.
The blasts happened within seconds of each other, according to a Boston Herald reporter who was among the 23,000 runners competing in the race.
The explosions occurred shortly before 3:00 p.m. as dozens of runners were crossing the finish line near Copley Square, packed with thousands of spectators and friends and family of the competitors.
The investigation is now being led by the FBI, which continues to collect evidence at the crime scene and to review footage from security cameras.
Officials have appealed to anyone who has still photos or video taken at the finish line around the time of the attack to provide that material to investigators.