in the aftermath of a fatal fire, one question remained. was it an accident or was it arson? it took the physics of a burning cigarette, the chemical composition of a flame, and a computer-simulated fire to determine how the fire started and who was responsible. for 25 years, ed and rosalie camiolo lived in an affluent suburb just outside of philadelphia. ed was a retired government worker. rosalie worked in the computer industry.

their only child, paul, a 31-year-old computer programmer, lived upstairs. he took care of his parents, since they had difficulty getting around. >> it's not that they were bedridden or complete invalids, but they certainly weren't athletic and able to respond, in my opinion, to an emergency situation. >> just before dawn in september of 1996, paul made an emergency call to the fire department. >> 911, what is your emergency? >> we have a fire in our living room. it's getting really bad. >> get out of the house. we have the fire department coming out. [ sirens ] >> when police arrived, they found paul on the front lawn getting dressed. paul said his mother and father had gotten out through the back door. when the officer went to the back yard to check, there was an explosion. she found rosalie on the back porch severely burned and barely conscious. but there was no sign of her

81-year-old husband, ed. firefighters later found him inside. he had been unable to escape. >> the victim that was located was in a rear bathroom, and he was in cardiac arrest at that time. >> ed camiolo was pronounced dead at the hospital. rosalie died, too, a result of smoke inhalation. >> how horrible it must have been for my uncle, what he went through to be burned, and my aunt, how horrible it must have been for her. >> the firemen at the scene didn't see anything suspicious. >> there was a general consensus that the fire was accidental in nature and most probably the result of the careless handling of smoking materials, either a cigarette or a match to light the cigarettes. >> paul camiolo told investigators his mother was a chain smoker and that she probably started the fire accidentally.

paul said he was asleep upstairs when he heard his father calling him. >> paul! paul! >> he said there was a small fire on the sofa, which his mother was trying to put out. he ran to the kitchen, got a pitcher of water and threw it on the sofa, but it made the fire worse. he told his parents to go out the back door, he called 911. then he went out the front door to his car. >> he was in his underwear, i believe, at the time, had his car parked out in front and had a gym bag in his car, and he felt he could get some shorts or clothes to put on. >> what doesn't make sense to me was paul's story. to this day i have problems with what he says happened. >> this incident raised eyebrows among investigators. >> he went in an entirely different direction. i mean, i think common sense dictates that you're going to make sure your folks get out of the house. and the way to make sure that your parents get out of the house is to follow them out of the house.

>> paul camiolo admitted his behavior was a mistake but said he was dazed and confused. >> you know, i remember feeling guilty about it because i was the able-bodied one. and i didn't get them out. >> but when a suspicious substance was found on the living room floor, all eyes turned once again to paul camiolo. that's why i run on quickbooks. i use the payments app to accept credit cards... ...and everything autosyncs. those sales prove my sustainable designs are better for the environment and my bottom line. that's how i own it.

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ed and rose camiolo were laid to rest in the family plot just a few miles from their home. the camiolos' lives before the fire had not been easy. their son, paul, was their primary caregiver. >> you know, he did have that responsibility to help assist his parents. he would do the grocery shopping for them. if they wanted something from a department store, a lot of times he would go to the mall and buy it and bring it home. >> investigators wondered whether paul may have had something to do with setting the fire. >> there was money there in the

form of insurance money. and that in and of itself is a powerful motive. >> i believe he received about $200,000 in insurance benefits. >> a second motive that some of the investigators believed existed was that paul camiolo was tired of caring for his infirmed parents. >> fire investigators searched through the rubble and found something very suspicious. >> in the center of the room there was a pattern that looked like perhaps it might have been associated with a liquid pour, what they refer to, when someone may have poured an accelerant. >> to see if an accelerant was used, investigators removed samples of the carpeting, the padding and the hardwood floor. the samples were sealed in paint cans to prevent any gases from escaping and sent to the forensic lab. gas chromatography can identify the molecular components of the samples, and the results showed

there was evidence of gasoline on the wood floor. >> and the single biggest piece of evidence for them to conclude this was an arson fire was the finding of gasoline in the hardwood floor, because how else would you explain gasoline in a living room? >> when the test results come back, it changes from i don't know to, wow, we have an accelerant here, this must be an arson, and that changes people's opinions. >> to prosecutors, the presence of gasoline meant murder. based on this evidence, prosecutors believe that paul poured gasoline on the living room floor while his parents were upstairs asleep. he then set the room on fire and called the fire department. the heat and smoke made it impossible for paul's parents to make it out of the house alive.

paul strongly denied these charges. >> my mother and father knew the truth, and god knows the truth. and that's all that mattered to me. >> paul camiolo was arrested and charged with two counts of first-degree murder. his request for bail was denied. >> i had no problem justifying arguing for the death penalty. i mean, i can't think of anything more vile than killing the very people that brought you into this world. >> they were saying i tried to burn them to death, you know? that's -- that's just, you know, horrible beyond words. >> the press depicted him as a cold-blooded killer. yet, his family stood firmly behind him. >> anybody that knew paul knew he couldn't do anything like that. he loved his parents very much. and they were a very devoted family. >> that boy was good to his parents. >> we were all there to support

him, and we all went to the hearings, and several of us visited him on a regular basis. we all believed that he was innocent. >> as the trial approached, paul camiolo and his defense team looked for some way to prove that the fire was an accident. >> i couldn't imagine how the gasoline got in there. >> there had to be another explanation as to why gasoline was in that floor. they get re-heated. re-nuked. and re-baked. and when leftovers are done... there's always stuff left over. new dawn platinum power clean calls dibs on those. it powers through tough, dried-on messes in seconds. even 48 hour stuck-on food. so go ahead, triple that recipe! a drop of dawn and grease is gone.

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the firemen responding to the camiolos' house fire were all volunteers, but one of them had an unusual background. steve avato was also an agent with the bureau of alcohol, tobacco and firearms. >> he had been a philadelphia policeman prior to going to the atf. so, he was not somebody just out of the academy. he had been someone involved in police work for a number of years. >> the atf took no part in this investigation, but personally, avato was dumbfounded when he learned paul camiolo had been charged with arson. to him, it just didn't make sense. >> that finding shocked me. i hadn't anticipated that. it seemed very difficult to explain how the gasoline would be in hardwood floor but not in carpeting and padding above it,

if a significant volume of gasoline was poured. >> and avato wasn't the least bit suspicious of paul's behavior on the night of the fire. >> it's not unusual for people in a fire to exit a building through the way that they're most comfortable exiting. if they typically come and go through the front door, no matter where they are in the house, they'll exit through the front door. >> avato told local investigators that he believed the fire was accidental, and he was roundly dismissed. >> they portrayed him in the media that he was, you know, an apprentice fire investigator that really was not experienced and really didn't have the qualifications to be offering opinions. >> he was treated like dirt by the locals and by the attorneys involved in this case. >> when the defense team learned about steve avato's opinion that the fire was an accident, they conducted their own investigation and hired dr. rick

roby, an expert on the science of fires. >> what makes it difficult is, fires burn up a lot of the evidence. >> roby studies fires while they're burning. to do this, he sets fires like this one in model rooms. fires progress differently depending on how they're set, the size of the room, airflow and hundreds of other considerations. all of this data is then entered into a computer. >> it's a fully 3d fire modeling software that actually allows you to model the development and growth of a fire in a building. >> for this assignment, roby and his staff built a virtual reality replica of the camiolo home. then they entered all known information about the fire into the computer. roby conservatively estimated

that it would take at least one gallon of gasoline to create a pour pattern the size of the one found in the living room. five or six minutes after paul camiolo called the fire department, the outside window exploded. the explosion was the result of what is called flashover. when flashover occurs, temperatures in the room get so high that items ignite even without coming into contact with the flame, as you can see here. >> and in fact, unfortunately, there are firefighters killed every year by having been caught in flashover conditions, because it happens so rapidly. sometimes it's very difficult to escape from those conditions. >> after roby entered this information into his computer program, he lit a virtual match. within 30 seconds, hot gas fills the room. within one minute, smoke and gas spread up the stairs to the second floor. and three minutes after

ignition, the living room would reach flashover, blowing out the window. >> the entire room becomes engulfed in flames because there's so much burning and so much hot gas that it's completely uninhabitable. >> but the police witnessed the window breaking five or six minutes after paul called the fire department. to roby, this meant that gasoline couldn't have been used to start the fire. >> he would have had a tough time actually getting to the front door without being engulfed in flames. that's one of the things our model showed. so, we look at the arson scenario and there is inconsistency after inconsistency. >> next, roby tested paul camiolo's story. paul said the fire started by accident with a cigarette or a match his mother had been using. at one minute, the fire would be about two feet tall and gathering strength.

at two minutes, it would be moving across the ceiling. at four minutes, temperatures and gas levels in the room would be fatal. at 5 1/2 minutes, the fire reaches flashover and the window blows out. this was consistent with paul camiolo's version of events. >> matches up with everything that paul camiolo was saying and with other objective evidence that he has nothing to do with. >> but important questions remained. if the fire was an accident, why was gasoline found on the living room floor? i have a cold

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i was horrified. it felt like i was in my own horror film. >> defense attorney thomas cometa strongly believed his client, paul camiolo, was innocent, that he never set fire to his family's home in order to kill his parents. >> facing the death penalty for a crime that he was convinced and we were convinced first of all he did not commit, but a crime that didn't occur, that this was an accidental fire. >> the reason that paul camiolo had been charged with first-degree murder was the gasoline found on the floors in

the living room, but paul's defense team was suspicious of this finding. >> they took samples of the carpeting, the carpet padding, and some newspaper, and there was no gasoline in any of those samples. it was only in the hardwood floor. and it was just inconceivable. how can you pour gasoline in a family room and not get the gas on those other items if that was going to be the cause of the fire? >> so the defense team hired john lentini, a nationally recognized fire expert, to find out what happened. lentini retested the samples of hardwood floor using atomic absorption spectroscopy. >> it's a way to measure the concentration of metals in a solution. >> the wood flooring was dissolved in acid, then analyzed to see how the solution is absorbed through the flame. the amount of light absorbed is proportional to the

concentration of the element in the solution. and what was the element found in the solution? lead. this meant that it was leaded gasoline on the camiolos' wood floors. but how did this happen? since leaded gasoline hadn't been sold in this country for over 15 years. >> many of the poorly constructed houses that i've looked at were built in the early '70s, and they were built by contractors who were cutting corners. >> flooring contractors often used gasoline as a thinner so the varnish would go onto the wooden floors more easily. this was cheaper than using high-quality thinners. >> no one refuted the fact that that was a common practice, that they did use gas in finishing of the hardwood floors. so, i am convinced that's where that gas came from. >> so that was really the moment where we said, here's the final piece of the puzzle. if this is leaded gasoline, it all makes sense, and it makes sense how it would be there and why.

>> forensic tests also revealed how the fire started. a cigarette dropped on to a polyurethane sofa will simply smolder. but when a match is dropped on the same material, it's almost like an explosion. and tests revealed that another aspect of paul's story was correct, that when he poured water on the fire, it got worse. >> the average person wouldn't know that polyurethane melts and then when you throw water on it, it actually flares up like a grease fire. >> when prosecutors heard about this, to their credit, they conducted their own test. they secured from the manufacturer the same fabric that was on the camiolos' sofa. >> and i cut off a 4-inch by 4-inch portion of this fabric, and we dropped a match on it, and it ignited immediately. and at that point, i knew that

the case was in trouble, serious trouble. >> and the alleged pour pattern on the living room floor? many now believe it was simply the result of normal wear and tear. >> you would expect that people walking back and forth on the carpet would thin the carpet, and therefore, any heat that's imparted on that would pass through that carpet area more quickly than in other areas. >> when all of this overwhelming body of evidence came to light, all charges against paul camiolo were dropped. >> in this business, you have people that for a certain amount of money will tell you anything you want to hear. these experts were not of that ilk. and no, it wasn't tough. it wasn't a sad day. it was the right thing to do. and if it's the right thing to do, then do it. >> i'm not saying that it was malicious and intentional. i'm saying that, unfortunately, they had gut feelings and years of practical experience that led them to conclude this had to be

an arson fire. so they let common perceptions outweigh logic and science. and luckily, logic and science prevailed in this case. >> paul spent ten months in jail, facing a possible death sentence for a crime that never happened. >> there are days i can't bear to look at pictures of my mother and father. because i -- i just remember the fire. >> he spent ten months in jail. that was liberty that was taken away from him that he'll never get back. it was a time that he should have been grieving for the loss of his parents, and instead, he was fighting for his own life. >> when asked how it felt to be right all along, not surprisingly, steve avato had no comment. but his colleagues spoke for him. >> his courage was later recognized by his fellow fire investigators when the international association of arson investigators named him

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