A smartphone can reveal a lot about a person.

“Your life is on your mobile device,” said Westfield defense attorney William Webster. “It’s very personal in nature, and really kind of an extension of you.”

Webster had that in mind after his client came to him with a quandary: Police wanted access to her smartphone and had obtained a search warrant. But officers couldn't get into the device without a passcode. The client, Carmel resident Katelin Seo, 37, was facing accusations of stalking and harassment. A Hamilton County judge ordered Seo to unlock the phone.

There was no specific case law that Webster could immediately cite, he told IndyStar, but something told him that being forced to hand over something so inherently personal was a violation. “At the time, it was hard for me to imagine that a defendant would be required to assist the prosecutor in the case,” he said.

After some discussion, Webster invoked Seo's Fifth Amendment right against self-incrimination.The Indiana Court of Appeals sided with Webster.

Next month, the Indiana Supreme Court will hear the case. Whatever the court decides could undermine either privacy interests and constitutional rights, or public safety and law enforcement, according to attorneys in the case.

Both sides told IndyStar the case, regardless of the outcome, could be argued before the U.S. Supreme Court.

Stalking case sparks legal battle

The male victim said the conversations were short, but he recognized Seo’s voice, according to court documents.

“Don’t play me, you’ve been warned.”

“Watch your back.”

The phone calls came on July 20, 2017 — the same day Seo bonded out of Hamilton County Jail after being formally charged with stalking a man she had dated, court documents show. The day before, Seo had signed an order forbidding her to have any contact with him.

That same month, police received another harassment complaint against Seo. The second case involved a woman whose two young children attended the Goddard School, where Seo worked, according to Webster. The woman reported receiving several menacing text messages, according to court documents.

“I’m sitting in my car deciding what I should do.”

“I can see them through the fence.”

In August 2017, Hamilton County Sheriff’s Office Detective William Inglis sought a warrant to search Seo’s iPhone 7 in connection with the first stalking case, court documents show. Inglis asked the court to compel Seo to unlock her cellphone and, if she refused, subject her to the contempt powers of the court, according to the warrant.

Police already had Seo’s phone, authorities said. They just needed the passcode to gain access to its contents, which police believed could contain evidence. A Hamilton County judge granted two separate search warrants — one granting the forensic download of the device and another compelling Seo to remove or give the passcode, according to court documents.

But the request didn’t sit well with Webster.

Reporting this story took time. Support reporters who bring you news that matters.

“So we just said, ‘She’s going to invoke her privilege and she’s not going to provide her password.’ And it went from there,” Webster said.

After her refusal, a Hamilton County judge found Seo in contempt and ordered her jailed until she complied with the order by unlocking the phone and either disabling the lock function or changing the passcode to 1234, according to court documents.

Later that afternoon, Webster says, he filed a motion to stay the contempt finding and appealed the ruling.

By the time the appeals court issued its opinion in favor of the defense in August, the stalking cases against Seo both had been resolved with plea agreements.

Records show Seo is serving prison time in the Department of Correction for an unrelated case.

Is giving up a password the same as forcing testimony?

The U.S. Constitution protects a person against self-incrimination. Under the Fifth Amendment, the government can't compel a person to be a witness or testify against him/herself.

Though Seo wasn't forced to say anything, her appeal argues that in seeking Seo’s password to unlock her iPhone, the state wants the “contents of (Seo’s) mind” to compel her to help police search her phone for potentially incriminating evidence. The password is essentially forced testimony, Seo argued.

Countering that argument, the Indiana Attorney General seized on an exception to the Fifth Amendment — the "forgone conclusion" doctrine. Under the doctrine, cited in a brief filed last year, a compelled act doesn't violate the Fifth Amendment if it doesn't provide authorities with any additional information.

That means the state "already has knowledge of those facts and can prove those facts through independent means."

In this case, the brief says, the state has "independently established" that the cellphone belongs to Seo, that she used it and that she knows the password. The state also says it has evidence showing that Seo used the cellphone to talk to the male victim.

By having her unlock the phone, it’s not learning anything new, the state said. So the exception applies.

Seo says that isn't enough.

"There is no foregone conclusion that anything exists on (Seo's) phone," Seo's brief said, meaning that the state hasn't established what it expects to find on the device—just that the device belongs to Seo. That's not sufficient information to get the passcode, Seo argues.

“No one’s suggesting that they can’t obtain a password, it’s just that they have to reasonably identify what they’re looking for,” Webster said.

But several states, not just Indiana, take issue with this contention. A separate brief filed this month in support of Indiana by Utah, Pennsylvania and others says the appeals court is misconstruing the Fifth Amendment by applying the doctrine to the phone's contents rather than the unlocking.

“This is no different than if police get a search warrant (to your home) and you lock the doors and refuse to unlock them,” said Stephen Creason, chief counsel of the Appeals Division at the state Attorney General’s office. “The law has never been nor does it make sense that police couldn’t go into your house."

In an interview with IndyStar, Creason disputed the notion that the state hasn’t provided enough information to show it knows what it’s looking for on Seo’s phone.

“We’ve been pretty specific already,” Creason said, “We’ve been specific enough that a judge executed a search warrant."

The opinion being upheld might be a win for the Fifth Amendment and privacy. But when it comes to safety, some states say everyone will lose.

“Any time a suspect password-protected a device or a file, it would be impossible to force him to unlock it — even if the government had secured a valid warrant,” the supporting brief said. This would create a “zone of lawlessness” for criminals to operate in.

Suspects, or anyone for that matter, usually don’t keep paper records anymore, Creason said. “Now they store it digitally on devices locked with passcodes. It would be much harder to gather evidence of illegal activity.”

A law expert told IndyStar the very core of the Fifth Amendment (the right against self-incrimination) already protects criminals.

"It's already true that the Fifth Amendment allows more crime," said Laurent Sacharoff, a law professor at the University of Arkansas. "It's kind of built into the Fifth Amendment, the assumption that, yes, people who commit crimes will get away with it sometimes."

Why police can't hack a suspect's phone

But with the device already in their possession, can't police simply hack a suspect's phone?

"The answer is, it's getting harder and harder for that to be true," said Von Welch, director of Indiana University's Center for Applied Cybersecurity Research.

When cellphones first came out, Welch told IndyStar, a passcode was just something the phone checked to give you access, like someone asking you for the password behind a door and then letting you in.

"As phones starting using encryption more and more, they’ve become more like safes. Unless you know the combination, you really can't get into it without a lot of work."

Encryption played a role in the appeals court's decision. The iPhone in Seo's case was locked, the opinion said, therefore the contents of the phone are encrypted. "Even if the digital contents of the phone’s storage could be extracted from the phone, those contents would still be undecipherable without also un-encrypting the contents," the court said.

In other words, "the documents (on your phone) don’t really exist, they’re just a bunch of numbers and code," Webster said. "By putting in your password, it’s the encryption key that recreates all of these documents. So then it’s a situation where, can you compel someone to recreate documents that really don’t exist?"

Law enforcement possibly could hack a phone if there's some flaw in the device, Welch said.

"But really what that means (is) you're willing to spend a lot of money to have someone hack into the phone for you," Welch said. "And that’s becoming harder as cellphones improve security."

The issue here, Welch said, is that the specificity of a search warrant can more easily be applied in a "physical world."

"And so, unlike a warrant for searching a house which says, 'We’re going to search for a particular car so we're going to look in the garage.' Once you unlock a phone, all of its contents are laid bare. So you don’t have an ability to just unlock text messages from a certain time."

As technology becomes increasingly sophisticated and secure, a dilemma emerges and deepens.

"We’re wrestling right now with how much security (we want) around our computers — do we want to make that as strong as possible — and realizing when we make security that protects citizens from criminals, that also makes it harder for law enforcement."

When asked if public safety was a concern, Webster reiterated that police can still gain access to a person’s cellphone — they just need to be more specific about what it is they’re seeking.

“If police came in (and) raided my office because they thought I was involved in child pornography, they would have some other evidence to support that,” Webster said. “All the courts are saying is, identify (that). ‘We believe you have these pictures on your phone, here’s why,’ or, ‘We believe these text messages occurred, here’s the other evidence we have to support that.’ ”

Bolstering his argument, Webster believes, is the resolution of Seo's first two criminal cases.

“The state had enough additional evidence that they went ahead and proceeded with their case,” he said. “My client still hasn’t provided her password, and all of her criminal cases have been resolved."

Creason acknowledged that the cases were resolved but said that doesn’t mean there was no use for Seo’s phone.

“It’s important to remember they went forward with the case by allowing her to plead guilty to a couple of charges,” he said. Had they possibly obtained more evidence, “they might not have been so willing to dismiss.”

Creason listed three possible consequences if the appeals court’s opinion is upheld:

Some cases could never be charged because the only evidence exists on a computer, smartphone or other device. Cases might get dismissed because the critical evidence to show someone has committed a crime is on a locked electronic device. “The state would have to make deals for lesser crimes because the defendant was able to hold that over their head and prevent that from getting evidence.”

"If someone can just refuse to follow court orders, then that necessarily invites lawlessness," Creason said. "There’s a court process. There’s a proper way of challenging court (orders). Refusing to comply is not one of them."

The outcome

In addition to multiple state attorneys general on Indiana's side , the case has drawn the attention of the American Civil Liberties Union and the Electronic Frontier Foundation, a digital rights group. Both groups have filed a brief supporting Seo in the case.

"This is an issue that courts are starting to struggle with and figure out what the right approach is to handling these issues, particularly as technology develops," Creason said.

Ken Falk, the legal director of ACLU-Indiana, told IndyStar that the case concerns "the very important question of the privacy interest that we have, or don't have, in our electronic devices and thus our electronic communications."

"The question in this case is whether being forced to unlock those communications is something that should be deemed to be protected by our right against self-incrimination," he said. "And it’s an uncertain question. We’re dealing with something that was obviously not considered by the founders."

The U.S. Supreme Court has yet to consider the issue.

"It’s not an issue that is going away," said Andrew Crocker, an attorney with EFF. "Whether the Supreme Court will get involved is always very hard to predict."

Both sides in the Indiana case say it likely won't end with here. Webster told IndyStar that if the court sided against Seo, he’d likely try to take the case further. And Creason says it’s a “real possibility” that the state will ask the U.S. Supreme Court to hear the case if their side does not prevail.

“The Constitution is a balancing act," Creason said. "We try to balance the public safety interest and privacy interest. The Supreme Court is tasked with deciding how to balance those things in cases where they’re opposed to one another. The scale can’t be tipped too far in one direction or the other. We’re asking the court to keep it in balance.”

Contact IndyStar reporter Crystal Hill at 317-444-6094 or cnhill@gannett.com. Follow her on Twitter: @crysnhill.