monster. i don't know how he became a monster, and, frankly, it doesn't matter how he became a monster. >> and the dna is what solved this crime. if this crime california police had several suspects in the robbery and murder of a retired couple. unfortunately, the friends uc evidence was inconclusive. ten years later, a determined forensic scientist with materials used by dentists found evidence that had previously been overlooked. and in so doing, made scientific history. ♪ bakersfield, california, known for its oil fields, wide

open spaces, and aggressive crime investigation unit. officials post pictures of their most-wanted criminals on the town's website, but they needed every trick they could think of to solve the case of clifford and alma merk, a retired couple who lived the south side. >> they loved to sit on the front porch. they had big trees in front, and it was shady in the summertime. >> one saturday morning, the merckmer me find the back door opened and a foul odor. i backed out and told my wife, something's wrong here, go across the street and call the sheriff's department. >> jim kristofferson was one of the first to arrive at the scene. >> the entire residence was ransacked, everything turned upside down, a chair was turned

upside down. anything in a drawer was tipped out and spilled on to the floor. >> when they got to the couple's bedroom, police discovered this was more than a robbery. >> clifford merck had been lying across the bed with his hands and feet pund with sobound withf cord. and he was obviously deceased. it was later determined he had been shot in the head twice. >> nearby, police found a pillow with two bullet holes. the pillow had been used to muffle the sound of the gunshots, but there were no spent shell casings in the home. >> so whoever committed the crime probably collected those casings to hate the evidence or to throw the investigation off track. >> the search team found alma merck's body in the second bedroom. >> it was a sliding panel in this location. as we slid it back, one could

see that there was a body placed in this closet. >> he told me that my mother, they found her in a wardrobe with a telephone cord tied around her neck. strangled. >> alma's jewelry and cliff's handguns were apparently stolen during the attack. investigators found two foreign fingerprints inside the home. one at the back door, the other on a sewing tray in the living room. in a search for suspects, a neighbor told police that he saw two men lurking around the mercks' home a few days earlier. >> he kept an eye on them until he lost visual contact with them because some trees obstructing his view. that was the last he saw of them. >> the mercks had no known enemies, and no one else in the neighborhood saw or heard anything unusual around the time of the murders.

investigators hoped that either the fingerprints or some other forensic evidence at the scene would lead them to the killer. anncr: right now, at the volkswagen memorial day event you can get a $500 bonus on top of all current offers on select volkswagen models including the sporty jetta s, now leasing for just $159.00 a month the remarkably versatile tiguan and the passat midsized family sedan. so, what's the shortest distance between you and a great deal on a new volkswagen? a straight line... to the volkswagen memorial day event. get 0% apr for 60 months on all 2014 passat gasoline models plus a total of $1,250 in available bonuses.

at cliff merck's autopsy, the medical examiner recovered two .25-caliber bullets from his skull. coincidentally, one of cliff's .25-caliber pistols was stolen during the robbery. investigators wondered whether cliff had been murdered with his own gun. >> we had been evaluating every .25-caliber automatic seized in the area as it came in to see if the ballistics would match the .25-caliber bullets that were removed from the skull of clifford merck. >> two months later, investigators found cliff midsection's gun. it was in the possession of a man whom we'll call dan jones at the time he was arrested on a drug charge. it was easily identifiable since cliff's initials had been carved into the handle.

>> that was cliff. he had his name on practically everything that he owned. he'd take a -- some kind of etcher and etch his initials on it, you know, just for identification. >> jones denied any involvement in the murder and said he bought the gun from an acquaintance, robert cowen. a manuel known to law enforcement. >> -- man well known to law enforcement. >> he supported himself by stealing, robbing people and stealing from restaurants, that type of thing. he had a long record of robberies and use of narcotics. >> robert cowen also had a partner in crime -- his brother, gerald. >> the brothers were involved in criminal activity. a lot of small-time stuff, public drunk, a lot of narcotics usage, some assaults. >> forensic scientists tested cliff's gun to see if it was the one used in his murder.

the gun of test-fired into a tub of water. as bullets go through the barrel, the lens and grooves which make the bullet spin leave marks on the outside of the bullet. >> they were designed with a certain direction of twist, a certain number of land and grooves, a certain measurement for those land and grooves. so those are intentionally put in by the manufacturer. >> surprisingly when the bullets from cliff's gun were compared to the bullets from cliff's autopsy, they did not match. investigators checked all of the local pawn shops and discovered that the cowen brothers had pawned some of alma merck's jewelry. with a search percent, police found several other items belonging to the mercks in the cowens' possession. >> he had a wallet. he had two social security checks which he was trying to

sell. he had all types of jewelry. >> but investigators did not find a .25-caliber pistol like the one used in the murder. investigators then compared the cowens' fingerprints and those of the drug dealer with the fingerprints found inside the mercks' home. they were astonished to learn that none of them matched. the cowen brothers' looked similar to the men seen walking near the home at the time of the murder, but the neighbor couldn't make a positive identification. all investigators had against the cowan brothers and dan jones was possession of stolen property. >> it got to a certain point where there was no fresh information coming in, and there was a lack of physical evidence tying the kau cowans to the crime scene. >> we would talk and say the same thing, we still think it's the same people, but we don't have the proof. >> i never lost hope.

i knew in my heart that the police would do their job and find the people that did this to mother and cliff. >> investigators confiscated every .25-caliber pistol they could find hoping that one of them would match the murder weapon. >> i maintained those bullets in my secured work area. i never returned them to the sheriff's property room knowing that i would one day get that firearm. >> eventually, there were other crimes to solve, other evidence it process. the murder of cliff and alma merck moved quietly into the unsuccessfuled file. ten years later, jim kristofferson was promoted to homicide detective, but he never forgot the murder of cliff and alma merck. >> the case had always bothered me mainly because of the circumstances, the way they were

murdered. and just knowing that there was that element out there still walking the streets, that hopefully hadn't done more killings. >> after a decade, the trail of the killer had turned cold. christopherson knew he needed forensic evidence to have any chance of solving the case. i make a lot of purchases for my business. and i get a lot in return with ink plus from chase

like 60,000 bonus points when i spent $5,000 in the first 3 months after i opened my account. and i earn 5 times the rewards on internet, phone services and at office supply stores. with ink plus i can choose how to redeem my points. travel, gift cards even cash back. and my rewards points won't expire. so you can make owning business even more rewarding. ink from chase. so you can. the numbers are impressive. over 400,000 new private sector jobs... making new york state number two in the nation in new private sector job creation... with 10 regional development strategies to fit your business needs. and now it's even better because they've introduced startup new york... with the state creating dozens of tax-free zones where businesses pay no taxes for ten years. become the next business to discover the new new york. [ male announcer ] see if your business qualifies.

ten years after clifford and alma midsection's murder, investigators in bakersfield, california, were no closer to making an arrest. >> we don't know who it was, if they're somewhere in the neighborhood still. it's really scary. very scary to think that they're still out this, they're not caught. and i tell you the truth, i really didn't think they were ever going to get caught. >> shortly after jim christopherson was promoted to homicide detective, he reopened the case, looking for any possibly evidence that might have been overlooked. >> when i opened up the case, it was very enlightening, first off. his no idea that the initial investigators had done so much work on it. they had talked to literally hundreds of people and interviewed hundreds of people

and had obtained a lot of good information. >> cliff merck's .25-caliber handgun stolen during the robbery was recovered a few months later, but ballistic tests revealed it was not the murder weapon. in searching through the files, christopherson discovered that there were several other men present on the night the cowan brothers sold cliff merck's gun to the drug dealer. when christopherson reinterviewed them now ten years later, one of the men present recalled an interesting detail. he recalled hearing the cowan brothers tell the drug dealer that the gun they were selling had been used in a crime. >> once this drug person took possession of the gun, he put a screwdriver down the end of the barrel and reamed it out. in effect, changing the rifle of the gun. >> with this information, greg

laskowski took a second look down the barrel of cliff merck's gun and saw evidence of what the informant was talking about. >> the land impressions at the muzzle or counsel of the barrel appeared to be altered. it wasn't obvious at first because it's an old gun. there was something about the crown and land impressions at that muzzle that were just different from the remainder of the impressions farther down the barrel. >> since only the end of the barrel had been altered, he needed a way just to examine the persian of the barrel that was unaltered. no one in the forensic establishment could help him. >> i contacted a number of known experts about what i was planning to do and how to do it, and they all wished me good luck. and so, you know, i hoped -- i kind was working on my own at

that time. >> but he remembered using a dental casting material called mikrosil in a case where he needed to see tool marks in metal. he decided to try that by putting it down the barrel of the gun. >> it consists two of parts -- a silicone rubber base and then a catalyst or hardener. when basically -- it comes in two tubes. when one squeezes a certain amount of the rubber material out and then a corresponding amount of hardener out, you mix the two together. in this particular case, we injected the cast into the barrel and let it harden. >> it took 15 minutes for the mikrosil to solidify inside the gun. when it hardened, laskowski slowly removed the cast from the barrel. >> it literally does not adhere to the substance that it's casting, it just records its surface detail.

it's like an egg on a teflon frying pan. one can see that one achieves a very true representation of the interior of the barrel, plus the fine detail. >> he cut away the portion of the barrel imprint destroyed by the screwdriver and then compared the remainder of the cast to the bullets that killed cliff merck. in an incredible turn of events, they were an exact match. this proved that clifford merck's own gun was used in his murder and that the cowan brothers had been in possession of the gun before it happen -- before it had been altered. even with this discovery, it still wasn't enough to prove murder. >> that was good circumstantial evidence, however it still did not place them inside the crime scene. >> there was one more piece of evidence about to be uncovered

that would point the finger at who killed clifford and alma merck. r76wh x2ó

for the first time in the history of forensic science, a cast made of the inside of a gun

was used to identify a murder weapon. the pistol used to kill cliff merck had been sold to a drug dealer by robert and gerald cowan. but for some reason, the cowans' fingerprints did not match those found at the crime scene. >> the person who attempted the comparison was unable to make a match, and he -- he failed to have another examiner verify his conclusion conclusions. >> this was a breach of protocol. the fingerprint examiner is required to have someone verify his or her conclusions. so the fingerprints were resubmitted for analysis, and this time the results were verified by a supervisor. the fingerprints found in the mercks' home matched robert

cowan. >> goes without saying that i was highly irritated and embarrassed for the department. >> i initially on the latent evidence being misread, i tend to believe that was probably a training issue. >> this was simply a situation where the original examiner was in over his head and couldn't handle it. >> armed with the fingerprint evidence and ballistic test results, robert cowan was arrested and charged with two counts of first-degree murder. >> took him back to the office and found where his fingerprints were definitely found inside of that house and asked him to explain that. and he just shook his head and kept his mouth shut and stayed silent and said he couldn't explain it. >> gerald cowan was also arrested for the murders but was later released because there was no forensic evidence linking him to the crime scene.

gerald cowan was later convicted of manslaughter for killing his father-in-law. he served only two years in prison for that crime before he was released on parole. prosecutors believe robert cowan was one of the men sear the mercks' home by the neighbor. based on forensic evidence, prosecutors say robert cowan and an accomplice broke in to the mercks' home through a back door. cliff merck probably went for his gun to defend himself, and robert cowan grabbed the pistol and turned it on cliff. [ gunshots ] >> the men bound his wife alma, locked her in the closet, and left her to die. robert cowan left his fingerprints on a tray found in the living room. and by the back door as he left. the cowans pawned some of alma

merck's jewelry, then sold the gun to a drug dealer who altered the rifling mark of the gun barrel. it wasn't enough to fool a forensic scientist with his newfound ability to see inside the barrel. >> something inside says hold on to these bullets, you're going to find the firearm. lo and behold, it happened. way down the line, almost ten years later. but time was on our side i guess in that matter. >> robert cowan was convicted two of counts of first-degree murder and was sentenced to death. >> when you look at what he did to this elderly couple who he had no reason to kill, he could have taken everything they had and tied them up and left. he didn't have to shoot them, he didn't have to shove mrs. merck in the closet and leave her to die. i couldn't find anything good about this man. i couldn't find anything nice about him.

i couldn't find any reason in the world why i felt he should be walking on the earth and breathing air. >> i'm glad they convicted him. i'm glad he's where he is. and i think that he deserves everything that he's getting for what he did to my mother. >> if they would let me, i would throw the switch or whatever it takes to do. >> the merck case took ten years to solve and required both perseverance and ingenuity. the result was not only a conviction but a new forensic test now used around the world when investigators suspect there has been tampering inside a gun barrel. >> this is where forensic science works where it always borrows or steals from its neighboring sciences or

methodologies. and that t takakes those and ust in a practical manner. >> i could not have won the case, not have gotten the death penalty without forensic science. >> i've had a long career, and it was one of the highlights of my career. [ sire not ] on a bitter other cold night, a family home went up in flames killing one man and leaving a second person injured. a witness blamed a kerosene heater. local investigators suspected arson. forensic science was needed to sort through the contradictions. was this an accident or cold-blooded murder? ♪ >> the weather in jackson, georgia, is usually warm most