FULLERTON (CBSLA) – Authorities believe that an improvised explosive device was responsible for an explosion which left a man seriously injured near a Denny’s restaurant in Fullerton Friday morning. A second undischarged IED was also found nearby.

The explosion occurred at about 8:50 a.m. near a shuttered Chase bank in the area of South Harbor Boulevard and Orangethorpe Avenue.

According to police, a 59-year-old man was holding an IED in his hands when it went off. He was rushed to a local hospital with severe injuries to his hands and face, Fullerton police said. Some of his fingers were also blown off. He is expected to survive.

Several nearby businesses were evacuated and the Orange County Sheriff’s Department bomb squad was called to the scene.

Police initially reported that they did not believe that the explosion was a criminal act. However, they later reversed course and confirmed it was caused by an IED. The bomb squad searched the area and found a second IED, about the size of a golf ball or baseball, with black powder and a fuse in it.

“They were small, but they were improvised explosive devices that were strong enough, clearly, to cause some serious damage to the individual that was holding it,” Lt. Jon Radus told reporters.

Witness James Thompkins, who is homeless, told CBSLA the suspect was also living on the streets.

“He was homeless, I didn’t know him personally, but nothing new, all kinds of homeless hang out behind this building,” said Thompkins.

The suspect is expected to face criminal charges, police said.

Harbor Boulevard was shut down in both directions for several hours, but reopened before noon. The evacuation order for the business district was also lifted.