The big lie continues with elizabeth vargas. What kinds of lies have you ever told your spouse? Little white lie, some big whoppers. But probably nothing like what you're about to see, lie after lie... See More
The big lie continues with elizabeth vargas. What kinds of lies have you ever told your spouse? Little white lie, some big whoppers. But probably nothing like what you're about to see, lie after lie that ended or maybe just began with an explosion. Not the kind that's a fight in the house, but a very real bomb. Going off. On a quiet september afternoon, as parents picked up their kids from day care, a scene straight from "the sopranos" rocked this suburban san diego neighborhood. I put the key in the ignition, turn it on, and just kaboom. It just was a very, very loud explosion. Just made my heart stop. Reporter: The victim was connie hoagland, a day care teacher, wife and mother. I saw connie laying in the middle of the street on her side, curled up in a ball in a pool of blood. There is glass, shrapnel everywhere, and my first thought was, "oh, my goodness. This is what it looks like in a war zone." Reporter: Someone had planted a pipe bomb in her truck, powerful enough to explode a small shack. I just remember my feet were in such pain, it felt like they were just jelly, like it was just they were just blown off. Reporter: Paramedics rushed her to the hospital. And it was just hard to see your mother like that and to not know what happened yet. So you're just confused. They literally had to rebuild her right leg. There's a rod in it and rebuild her left foot. I'm praying god don't let her die. Reporter: Did you have any idea who could have put that in your truck? That was the hard part. I just thought it was a random explosion. I couldn't think of anyone who would do that. Reporter: It didn't make sense to detective robert luke either. Who would want to kill a suburban housewife like connie? Maybe the bomb was intended for some else at the day care center? There was a lot of law enforcement people that actually took their kids there. One, was someone trying to target one of these people for a case that they're working? We know nothing about. Reporter: One of the policemen who was a parent of one of the kids at the day care center, might he or she had been the target? Exactly. Mistaken vehicle, right. Reporter: But this wasn't the first pipe bomb to turn up in the area. Two weeks earlier an unexploded bomb was found two blocks from the hoagland homement for detective luke, that was too much of a coincidence? Was there something about connie hoagland, something in her past that had come back to haunt her? Was there gambling debt? Was there some type of drug deals going wrong? We look at every angle there was. When you did question her family, her husband and her children, what did you learn? How did they strike you? They struck me as a very nice family. They stuck together. They were very proud of each other. They were very supportive of each other. Reporter: They were as all-american as a norman rockwell painting. Connie and larry fell in love AND MARRIED IN THEIR 20s. He was a professional photographer, charming, well liked and respected. Connie always had a smile for everyone and rarely spoke an unkind word. Both were active in church and taught bible study. Their kids, jill, jaclyn and jonathon. This wasn't a family with enemies, and, yet, as detective luke dug deeper, he discovered life inside the hoagland home wasn't as tranquil as he had thought. Like so many people, they were deep in debt and facing bankruptcy. Connie revealed larry was depressed. You describe a pretty marked personality change in larry. Yeah, a little more tense. Snapped more, just grumpy because of all the stress. No money and everything. I was just extra nice to him. Reporter: But the financial strain was taking its toll on larry. He took on extra work, making frequent business trips all the way to the east coast. He was traveling to pennsylvania a lot, to someone back there named bob. This was a client? Yes. Bob must have been a big client. That's what I thought, "okay, go back and make money." Reporter: So who was this mysterious bob? And where was the money from all those trips? That's what larry's business partner wanted to know, so he went snooping on the office computer that he and larry shared. The business partner was doing a search of previous web searches and came up with almost 23 different sites of various bombmaking information. Somebody at larry's office had searched on the internet 23 times how to build a bomb? Yes. Reporter: And that somebody was larry. He was the only one in the office when the searches were made. And there was more. His cell phone revealed a virtual blueprint of a life he'd hidden from his wife and kids. Larry hoagland was arrested. And jailed. From behind bars he delivered yet another bombshell. He'd been carrying on with another woman for three years. He said, "hi, connie, I just wanted to let you know, because it's going to get out, that I've been having an affair." Then he said, "but I'm dedicated to you ever since the day of the bombing. Reporter: I've been having an affair but I'm re-dedicated to you since the day of bombing? Exactly. And then he said, "and I didn't do it." Called me and said, I didn't do it. I didn't do it." And I said, "i know you didn't. I know you didn't." Reporter: But after 25 years of marriage, how well did connie and his children really know him? From behind bars he insists investigators have the wrong man. I did not try to kill my
This transcript has been automatically generated and may not be 100% accurate.