Sex assault conviction may be test case for testimony standards

7/23/12 - A story on expert witnesses Sunday incorrectly stated the name of Noe Perez's lawyer, David Lee Phillips.

The case against Noe Perez seemed lock-tight, and it was.

For the nine counts he faced for sexual assault and lewdness with a minor, a jury last year convicted him of eight.

A judge handed down a life sentence with the possibility of parole after 35 years, and that seemed to be the end of the case against Perez.

But now he is appealing his conviction - not because of the evidence against him, which included his wife witnessing the assault.

He's appealing because of one of the courtroom experts prosecutors used to convict him.

Perez's case is obscure - it received no media attention and his conviction is unlikely to be overturned, although he could receive a new trial.

But defense lawyers hope that the Nevada Supreme Court uses it to rein in what they describe as Nevada's Wild West attitude toward courtroom experts, who are routinely called to explain or dispute complicated evidence.

Depending on what side of the case you're on, the quality - and number - of experts often makes the difference between an exoneration or a conviction, and some cases rest solely on which experts jurors believe.

"In Nevada, you can be an expert in almost anything," said Norm Reed, a public defender. "There is no limit to who is an expert."

Nevada is unusual among the states in that it hasn't adopted standards for courtroom testimony. As long as the testimony helps the jury, it should be allowed to be heard, the state Supreme Court has ruled.

That kind of freewheeling attitude can lead to wrongful convictions, however. The 1980s and 1990s saw several breakthroughs in forensics, including the introduction of bite-mark evidence, hair and blood spatter analysis and medical work that led to an increase in "shaken-baby syndrome" cases.

But the reliability of those techniques was measured by whether they were successful in obtaining convictions - not whether they were actually reliable - and the last decade has seen many of the breakthroughs cast aside as "junk science." A number of innocent people have been exonerated after DNA or other evidence surfaced and cleared them.

The use of unreliable courtroom experts is to blame, lawyers say.

"We let these people come in and both sides put on experts and the jury decides what the truth is," said Scott Coffee, a public defender and president of Nevada Attorneys for Criminal Justice. "But the problem is that sometimes one side isn't based on science at all.

"When you don't have a scientific basis, you open up the floodgates to charlatans professing to be scientists, and that's a problem."


Perez traveled to Las Vegas in September 2008 to see a concert with his wife and their 13-year-old niece. They stayed at the Luxor, where Perez assaulted the girl in the room while his wife was in the shower. His wife came out of the shower to find the girl's underwear pulled down.

The girl said that in the months leading up to the incident, Perez began to show affection for her - touching her, calling her, admitting feelings for her and eventually kissing her.

Prosecutors believed that his behavior was typical of predators who "groom" their victim before assaulting them. They hired a local clinical forensic psychologist, John Paglini, to testify about grooming.

Paglini has spent more than a decade in the courts doing child custody evaluations, domestic violence and sex abuse cases. He's done more than a thousand psychosexual evaluations for the department of parole and probation, and grooming is one of the subjects he has to consider in the evaluation, according to prosecutors.

But he's never performed a study of grooming and hasn't written about it in any scientific journals. This was his first time testifying about it. And since he had never evaluated Perez, he mostly spoke in generalities about grooming behavior.

Perez's lawyer, David Lee Phillips, cried foul. He objected to Paglini's testimony before and during the trial.

The psychologist was not an expert on the subject - he hasn't devoted his career to studying grooming behavior - and shouldn't have been allowed to testify, he said.

"It's not a proven science. It's a behavioral thing," Phillips said of grooming last week. "How can you tell that this was in the mind of this guy? ... When was it that he decided he was going to groom this person?"

Phillips appealed the conviction to the Nevada Supreme Court, which this year asked two groups - the criminal defense lawyers' NACJ and the Nevada District Attorneys Association - for their opinions on the case. The organizations came to contrasting conclusions.

The district attorneys wrote that Paglini's testimony was relevant. If the crime was a jewelry store burglary and the evidence showed the suspect printed off diagrams of the alarm system and points of entry, wouldn't that evidence be allowed in the courtroom, they argued.

Besides, the prosecutors wrote, courts across the country have allowed grooming testimony.

But the NACJ argued that the judge should not have allowed Paglini to testify - the doctor's credentials weren't properly vetted, he had never testified or written a peer-reviewed article about grooming, and besides, it wasn't relevant to whether he committed the crimes in the Luxor hotel room. In short, the testimony biased the jury.

The justices haven't ruled on the case yet, but they have a few options for dealing with grooming experts - they could send it back to the District Court to sort out whether Paglini's testimony was proper, they could make that decision themselves and set a standard for future grooming experts, or they could set a more defined role on the use of all experts in Nevada courtrooms.

The latter is unlikely. But some lawyers say it's needed.

"We do need standards in Nevada," Clark County Public Defender Phil Kohn said.

Robert Langford, a former prosecutor who is now a defense attorney, said juries are too often influenced by expert testimony.

"That's why it might be better if there was a clear-cut standard for when expert testimony can be allowed in," he said.

Despite the power of their testimony, there is no national standard for who can be an expert - no licensing program, no registry, no scientific consortium that weighs in on whether the person influencing the outcome of a criminal or civil trial is even using science to reach their conclusions.

The legal system has inherent safeguards against obviously reckless experts. Lawyers don't want to introduce someone who's clearly not credible to jurors. And judges can prohibit an expert from testifying, although lawyers here say that rarely happens - judges just let the person speak and leave it up to the jury to decide if they're credible.

What Nevada's highest court could do is what its counterparts have already done.

The federal courts, and most states, have some defined standards for who should be an expert, based on series of U.S. Supreme Court decisions in the 1990s known today as the "Daubert" standard.

The standard requires judges to weigh a series of factors before admitting expert testimony, such as whether the testimony derives from the scientific method, whether the theory or technique can be tested, whether it's accepted by the scientific community and whether it's been subject to peer review.

The testimony doesn't have to meet all of those guidelines, but it can better stand up to scrutiny if it does. The goal is to determine the reliability of the testimony so that jurors are given the best information, according to Robert Correales, a professor at the Boyd School of Law at the University of Nevada, Las Vegas.

"The evidence has to be good evidence," he said.

Daubert has its flaws, Correales said - some states have made the standard too restrictive, prohibiting testimony on new scientific fields and other areas such as the social sciences that sometimes can't be tested, and it places a burden on judges to make tough decisions on subjects on which they themselves are not experts.

But he said that it would be better than Nevada's standard, which is basically nothing.

The willingness of judges to defer to attorneys and jurors to sort out whether something is science can have serious flaws, as the last several decades have shown.

When police and prosecutors began using forensic dentists to identify suspects who bit their victims before assaulting or killing them, it sounded like a bold new way to catch bad guys.

"They sounded like they knew what they were saying," Correales said of the dentists, "but the reality was they really had created a pseudoscience out of it."


By any standard, Kim Ancona's 1991 murder in a Phoenix bar was brutal. The cocktail waitress was found dead in the men's restroom, raped and stabbed in the back several times.

Detectives quickly zeroed in on Ray Krone as a suspect after finding his name in her telephone book. Krone had recently driven her to a Christmas party, and one of Ancona's friends told police that she was going to meet him after she visited the bar, according to a 2005 Phoenix New Times article.

Officers pulled Krone in for questioning and took hair and blood samples. They noticed his crooked teeth and wanted his bite marks, so Krone bit into a piece of foam and handed it to them.

Police arrested him and Krone was found guilty in two trials - the first was thrown out on a technicality.

In both trials, the prosecutor's case relied heavily on the testimony of Las Vegas dentist Ray Rawson, then a Nevada state senator and later university system regent.

Rawson told jurors that Krone's crooked teeth were responsible for a bite mark on the victim's left breast.

Even though nine other dentists disagreed with Rawson, the jurors' opinions were the ones that mattered, and they agreed with him. They cited Rawson's testimony as the reason for convicting Krone the second time, according to the New Times story.

Krone spent more than a decade in prison, two of them on death row, before DNA cleared him. He was released in 2002.

Bite-mark science has been largely discredited since Rawson testified against Krone. One study showed that the field was wrong two-thirds of the time, and it's rarely used it courtrooms today.

Rawson still lives in Nevada and volunteers his time with the Clark County coroner's office, using dental records to identify the dead and, on occasion, to identify bite marks.

He said last week that it's no longer considered ethical among forensic dentists to attribute bite marks to one person; instead, they say whether the suspect can or can't be ruled out from the marks.

A national board has also raised the standards for forensic dentistry, he added.

"That's a good thing," he said. "After all, we're after the truth. It's very sobering to think that someone might spend time in prison or on death row for something that isn't a strong, defined science."

Rawson said he can't talk about the specifics of Krone's case because of the potential to be sued.

He was hardly the only one who made mistakes in Krone's wrongful convictions. The authorities were staggeringly incompetent, the New Times reported. Detectives ignored glaring evidence that they had the wrong guy. Lab technicians lost some evidence and missed testing items that would have cleared Krone.

They identified the real killer soon after Krone was cleared. He was already in prison for a sex crime.


Rawson said he expects many areas of forensics, including DNA, considered the most unimpeachable of evidence, to become more reliable in the coming decades.

Kohn, the public defender, said there are still glaring problems in Nevada's courts, such as the way eyewitnesses are used. Even though science is starting to shed a light on the problems with eyewitness accounts, he said some local judges won't let defense lawyers introduce experts to address the subject.

"We all know all across the country that almost all the wrongful convictions are because of wrong eyewitness identification," Kohn said.

Clark County District Attorney Steve Wolfson declined to comment on the use of experts in the courtroom. But his predecessor, David Roger, said he did not believe that Nevada needed to set limitations on them.

"I have a great deal of faith in jurors," he said. "I think that they can sort out what is fact and what is fiction when listening to experts. So I think if you have good advocates on a case, they can effectively cross-examine an expert who is testifying beyond his or her area of expertise."

Roger believes that Nevada's liberal position on expert testimony can be attributed to trial lawyers not wanting judges deciding who can testify in a case.

For Phillips, he's hoping Perez will have his case overturned. But he now thinks that the case could set an important precedent.

"If we're going to be sending people to death row, we should be a little more in depth with what we're doing, have a little better system," he said.

Contact reporter Lawrence Mower at or 702-383-0440.