CHEHALIS, Wash. -- Kevin Williams was checking his mail when his mailbox exploded, sending him through the air.

“Just as I reached into the mailbox door. The only thing I remember is a very loud blast,” Williams said.

“I found him laying about 12 feet from the mailbox on his back. He wasn’t moving. I thought he was dead,” neighbor Dean Hanson said.

“I leaned over and shook him and yelled his name and he kind of ‘What happened? What happened?’ and I was just glad he was alive,” Hanson said.

Police are trying to determine what type of explosive was in the mailbox and who put it in there.

“The incident was obviously very serious, it knocked him unconscious. We feel very fortunate as I’m sure he does that there weren’t further injuries,” Sgt. Stacy Brown with the Lewis County Sheriff’s Office said.

“I can’t hear out of my right ear right now, and the vision in my right eye is blurred,” Williams said.

Police said they don’t believe the crime was random, but Williams said he doesn’t know if he was the bomber's target.

“Nobody knows who’s going to check the mailbox. Could be my daughter, could be my granddaughter,” Williams said.

Williams told KIRO 7 Eyewitness News that until he has answers, he’ll be looking over his shoulder and he plans to have a gun by his side at all times.

“No, no, I don’t feel safe,” Williams said.

The U.S. Postal Inspection Service is joining in on the investigation.

Williams clothing in addition to the remains for the mailbox will be tested for explosive residue.

Investigators said they hope that figuring out what type of explosive was used may help lead to the suspect.