new jersey bomb
An explosion that went off in a garbage can Saturday morning in a New Jersey beach town likely was timed to disrupt a Marine Corps charity run, authorities said.

Three pipe-bomb-type devices wired together were found near the boardwalk in Seaside Park. No injuries were reported and a four-block area was evacuated for most of the day, authorities said.

An initial examination showed the devices were rudimentary, with some type of timer, and only one of them detonated, two federal law enforcement officials told CNN.

Al Della Fave, a spokesman for the Ocean County prosecutor's office, said he believes the blast was meant to affect the Seaside Semper Five race.

"If it was just a matter of minutes, in terms of difference, there would have been a good number of people running past that explosive device" because of its location along the race route, Della Fave said.

Registration problems at the starting line delayed the start of the race, which meant no one was near the garbage can when the explosion happened, a law enforcement official said.

"We were lucky," the official said.Just after the explosion, Della Fave said, the area was placed on lockdown, and police deployed bomb detection dogs. He said no additional devices were found after the dogs completed their sweep. Race officials and local authorities canceled the event, race organizers said.

"It is a real shame that that charitable run that does so many great things for the Marines is now canceled," Della Fave said. "There's no word on when it will be rescheduled, but that's where we're at right now."

The FBI's Joint Terrorism Task Force will lead an investigation, with help from other federal, state and local officials, to find out who is responsible, an FBI official said at a news conference Saturday afternoon. "We're out there conducting interviews, we're out there securing evidence and we're making sure there is no stone left unturned," said Brad Cohen, acting special agent in charge of the Newark office.

Bomb experts will analyze the device and how it was made, according to CNN senior law enforcement analyst Tom Fuentes.

"It could be somebody that has grievance against the US military, possibly the Marine Corps specifically, and have nothing to do with an overseas-inspired attack like ISIS. So it still could be terrorism without being international, without being al Qaeda or ISIS or another affiliated group."

Three years ago, on April 15, double bombings near the finish line of the Boston Marathon left three people dead and more than 250 others wounded. A fourth person, an MIT police officer, was killed three days later during a manhunt for the bombing suspects.

Bombing suspect Tamerlan Tsarnaev died from gunshot wounds after his brother ran over him in a shootout while trying to escape. His brother, Dzhokhar Tsarnaev, was found guilty of 30 counts related to the bombings and sentenced to death.