Jerry McLaughlin had only just crossed the finish line at the Boston Marathon on Monday when he heard an explosion go off, followed by another.

“I was probably 150 yards past the finish line,” McLaughlin, an Air Force and National Guard veteran, told TheBlaze. “You receive a blanket and food and proceed to pick up your baggage. Then we heard a boom, so we all turned around. Immediately there were tons of police officers there and they were pushing people to go down the street.”

He said he initially thought the sound was caused by an exploding transformer. “When you turned around and saw the smoke, we knew it wasn’t,” he said.

McLaughlin, 50, had flown into Boston from Williamsport, Penn., just for the race. He was staying by himself at a Hilton hotel near Logan International Airport.

“Its amazing that it was that close to the finish line,” he said. “It’s shocking that something like that could happen. We live in a challenging world right now.”

Reports surfaced just before 3 p.m. ET of explosions, two total, that took place at the tail end of the marathon. Authorities have denied that a suspect is in custody, though some news outlets have reported that one there is a person of interest, a Saudi Arabian National, and he has been detained by Boston police. Three have now been confirmed dead from the blasts.

It took McLaughlin roughly two hours to get back to his hotel from the race. He said there was no cell service so most people in the area were texting each other to check on family and friends. When his cell service came back, he said he received several calls to make sure he was fine.

Asked to share any further details on his experience, McLaughlin offered profuse praise for the police, marathon volunteers and emergency crew on scene. “I don’t think you can say enough about the first responders,” he said. “It was an incredible response and as I sat there and watched it, it was unbelievable how quickly not only the volunteers by the police and emergency crew– it was incredible the response. I was very amazed by that. Impressed, is probably a better word.”

Another eyewitness told TheBlaze that the entire scene was “surreal.” The first explosion occurred just minutes after LeeAnn Yarbor, owner of the San Diego Run and Tri Club, crossed the finish line.

“Nobody knew what was going on,” Yarbor recalled. “We just saw police running towards the finish line and no one could tell me what was going on.”

“You could actually feel the whole vibration from the blast go through your entire body,” she added.

She said her family was thankful to God that she wasn’t harmed in the horrific attack.

Follow Eddie Scarry on Twitter @eScarry.

TheBlaze’s Jason Howerton contributed to this report.