The science of DNA analysis was non-existent in 1980. And although DNA evidence was collected at that time, is likely that the evidence became unintentionally cross-contaminated due to evidence collection procedures.
According to Cousino, two weeks after the murder of Sister Pahl, investigators conducted a consented search of Father Robinson's apartment. They were looking for a specific type of weapon and when a letter opener was found, it became a piece of evidence that was of great interest to investigators.A pattern of clues
Cousino became involved with the murder investigation in 2004 due to his expertise in blood stain transfer pattern analysis. In this case, he looked for consistency in the different shapes of the stains and size of the object that made the marks in the altar cloth, and ultimately on Sister Pahl's body. For his part of the analysis, Cousino visually examined of all of the blood stains for transfer patterns and measured and photographed the altar cloth to compare the patterns in the cloth for consistency.
"The blood stain comparison did give us a good possible weapon," Cousino says.
In order to run additional tests, investigators needed more DNA evidence. Sister Pahl's body was exhumed for a second autopsy.
During the 2004 autopsy, a section of Sister Pahl's jawbone was removed to extract molars as DNA evidence. Ironically, the removed section of her jawbone contained a distinctly shaped puncture wound, consistent with those found on the altar cloth and with the letter opener found at Father Robinson's apartment.
The altar cloth and the letter opener were compared separately in the 1980s, so a likely connection wasn't as easy to make.
"Our analysis of the evidence was just a little bit different than it was in the 1980s," Cousino says. "We looked at the same evidence, but in a different way." Cousino stresses the importance of the investigation by all of the detectives involved with this case.
"They did a good job back then, but they just didn't have quite enough to charge Father Robinson at the time," he says.Something old, something new
Even though Cousino believes the advancements and the integration of DNA evidence is very influential in cold case investigation, he also says that Automated Fingerprint Identification System (AFIS) is very important as well.
He explains sometimes latent palmprints are stored in the evidence room for years, and when a case is re-opened, prints can be submitted to AFIS for a possible match.
"It's really what allows cold case squads to exist, because AFIS is the newest technology that is really helping," Cousino says.
Dr. Henry Lee, founder and professor of the Forensic Science Program at the University of New Haven, Connecticut has assisted with more than 6,000 case investigations in the past 40 years.
He also believes another important aspect of cold case investigation includes fingerprint analysis.
"We solved quite a few cases recently because the evidence we re-examined had a latent print which linked to the suspect," Lee says.
"With a little luck, maybe you can find some new clues to solve cold cases."
Dynamics in relationships are completely unscientific compared to DNA or AFIS, but knowing the dynamics between suspects and victims is important, because it could change over the years. When detectives conduct interviews with witnesses who knew or were involved with the suspect during the time a crime was committed, new clues can emerge.
"Relationships may have changed over the years, so the witnesses might be a little more forthcoming," Cousino says, and adds that in a cold case reinvestigation, "you can't overlook anything."
Of course, there is a caveat: time, which can either help or hinder an investigation.
Winnebago County (Illinois) Coroner Elizabeth "Sue" Fiduccia agrees.
"The problem is, witnesses tend to move and they die, so if identification is made when you're trying to solve a cold case, it always gets that much harder," she says, "because those are the kinds of things that will change." The longer a case remains cold, the more difficult it becomes to solve, even though the evidence will always stay the same.