My past two posts have discussed Big Data:

A Google Anon explains social media bots (March 19, 2018)

The alarming world of Big Data (March 20)

Today’s post looks at Big Data’s role in crime solving. Police in Raleigh, North Carolina, sometimes use Google data to investigate crimes. They are not the only law enforcement agency to do so. Austin, Texas police were able to obtain information from Google in order to trap the 24-year-old man who was sending incendiary devices around the city.

On March 15, 2018, Raleigh’s WRAL.com posted an article about the subject. Google has received an increase in law enforcement requests for the Silicon Valley giant’s data (emphases mine):

Google’s most recent transparency report shows that there were about 5,200 search warrants requesting user information in the U.S. in the first half of 2017, an all-time high. User information requested through subpoenas and other court orders accounted for more than twice that number. The company produced at least some data in response to requests in the first of half of 2017 about 81 percent of the time.

The article says that it is unclear whether Google data actually helped Raleigh Police in four criminal cases:

Google declined to say whether it released data in any of the Raleigh cases, and it’s unclear from the search warrants exactly what information was seized or whether it’s been effective in moving the investigations forward.

Of the four cases, only one has resulted in an arrest.

Tyron D. Cooper was charged Oct. 13 with the murder of [Nwabu] Efobi, the taxi driver gunned down in east Raleigh. But the related search warrant shows data wasn’t received from Google until months later.

Cooper’s attorney, Christian Dysart, declined to comment on the case.

Two issues are at play here. The first is the amount of data people inadvertently give Google via their accounts and GPS. The second surrounds the manner in which the data are requested.

On the first issue, Google makes money by selling location data, which are:

immensely valuable to Google, one of the reasons the company collects and stores the information on users of both its Android operating system and, in some cases, mobile apps such as Gmail.

Most people with Google accounts probably do not realise how much they are telling the company — and others — about themselves:

“From an average smartphone user’s perspective, it’s a little surprising once you start to learn the full scope of information about our locations and whereabouts and activities that companies like Google hold,” said Nathan Freed Wessler, staff attorney with the American Civil Liberties Union’s Speech, Privacy and Technology Project.

People are mistaken if they think that turning their devices off turns off the tracking:

Users can switch location tracking off to prevent the device from pinging GPS satellites. But if it’s on a cellular network or connected to Wi-Fi, the device is still transmitting its coordinates to third parties, even if they’re far less accurate than GPS.

In the past, at least, turning off that technology has been no guarantee of privacy.

Business and technology news site Quartz discovered late last year that Google continued to track devices even when all GPS, Wi-Fi and cell networks were supposedly disabled. The tech giant says it has updated its software to stop the practice.

For its part, law enforcement makes frequent use of cellular network data to build cases.

That’s not so bad, we think. After all, they’re only catching criminals, not ordinary people. However, last year in Raleigh, police created a digital cordon around certain serious crime scenes:

On a satellite image, they drew shapes around the crime scenes, marking the coordinates on the map. Then they convinced a Wake County judge they had enough probable cause to order Google to hand over account identifiers on every single cell phone that crossed the digital cordon during certain times.

In at least four investigations last year – cases of murder, sexual battery and even possible arson at the massive downtown fire in March 2017 – Raleigh police used search warrants to demand Google accounts not of specific suspects, but from any mobile devices that veered too close to the scene of a crime, according to a WRAL News review of court records. These warrants often prevent the technology giant for months from disclosing information about the searches not just to potential suspects, but to any users swept up in the search.

These can be quite large areas:

The demands Raleigh police issued for Google data described a 17-acre area that included both homes and businesses. In the Efobi homicide case, the cordon included dozens of units in the Washington Terrace complex near St. Augustine’s University.

The account IDs aren’t limited to electronics running Android. The warrant includes any device running location-enabled Google apps, according to Raleigh Police Department spokeswoman Laura Hourigan.

“At the end of the day, this tactic unavoidably risks getting information about totally innocent people,” Wessler said. “Location information is really revealing and private about people’s habits and activities and what they’re doing.”

This appears to be a legal method, as it concerns public safety:

Hourigan said Raleigh police investigators use these search warrants on a case-by-case basis and consider Fourth Amendment protections against unreasonable search and seizure.

“This technique is used in extraordinary circumstances because the department is aware of the privacy issues that the tactic raises,” she said in an email March 9.

According to Wake County District Attorney Lorrin Freeman, police are following best practice by:

targeting narrow areas and specific time windows. She points out that data investigators receive from Google contain only anonymized account numbers without any content included.

“We’re not getting text messages or emails or phone calls without having to go through a different process and having additional information that might lead us to a specific individual,” Freeman said.

On the other hand:

After five years as a Wake County prosecutor, Raleigh defense attorney Steven Saad said he’s familiar with police demands for Google account data or cell tower records on a named suspect. But these area-based search warrants were new to him.

“This is almost the opposite technique, where they get a search warrant in the hopes of finding somebody later to follow or investigate,” Saad said. “It’s really hard to say that complies with most of the search warrant or probable cause rules that we’ve got around the country.”

And:

[Jonathan] Jones, the Elon professor and former Durham prosecutor, expressed similar concerns after reviewing the warrants. In particular, the fire and sexual battery cases didn’t present evidence that the arsonist or the attacker had a cell phone, he said.

“In those cases, the evidence provided to establish probable cause seems very thin to me,” Jones said. “These amount to fishing expeditions that could potentially snare anyone in the vicinity with a cell phone, whether they were involved in the crime or not.”

In conclusion, perhaps we need to be more aware of the information we’re giving out every day and how it could be used:

Most modern phones, tablets and laptops have built-in location tracking that pings some combination of GPS, Wi-Fi and mobile networks to determine the device’s position.

This is no doubt only the tip of the Big Data iceberg. We would probably be shocked if we knew the full story.