Nowadays, getting away with murder is harder than ever, thanks to advances in forensic science that enable crime scene investigators to tie individuals to their crimes through everything from DNA evidence to gun residue and blood splatter analysis.
It's become even tougher with the use of computer technology to track not just the physical footprints of suspects, but the digital trail they've left as well.
For example, the high profile Florida murder trial of Casey Anthony may not begin until May, but ever since the remains of Anthony's missing daughter Caylee were found in December 2008, the media has been in a feeding frenzy over each new revelation that might point to the mother's guilt.
One of the most damning of these revelations came when the results of an inspection of Casey Anthony's home computer were revealed. According to this inspection, someone using the young mother's computer had done an Internet search of such terms as "neck breaking" and "how to make cholorform" (sic).
As highly publicized as the Casey Anthony case may be, it's hardly the first time that police investigations have turned to Internet search engines to help make their case.
In 2005, prosecutors in North Carolina tried Robert Petrick for the murder of his wife, Janine Sutphen. Sutphen's body had been discovered floating in a Raleigh lake two years before.
Supporting their arguments that Petrick had killed his wife was the discovery that he had researched the words "neck," "snap," "break," and "hold" on the Internet search engine Google before his wife died.
In fact, forensic investigators dug even further, searching nearly a dozen computers seized from Petrick's residence. They found that just four days before he reported Sutphen missing on Jan. 22, 2003, Petrick had gone online and researched lake levels, water currents, boat ramps and access to and around Falls Lake.
Condemned by his own Googling, Petrick was found guilty.
In January 2005, police tried to piece together clues in the hit-and-run death of 55-year-old Gurdeep Kaur, a cook struck and killed while walking home in Lafayette, Calif.
Analyzing debris recovered from the scene (including a hood ornament), they determined that the vehicle was a dark-colored Jaguar built between 1995 and 2003.
The trail led police to Lee Harbert, a San Francisco Bay-area investment banker with three DWI convictions, and the black 2000 Jaguar VandenPlas in his garage. Although the car had been recently cleaned, body damage and one of Kaur's earrings found in the windshield well made it clear that Harbert had hit the victim.
But without any witnesses, how would prosecutors rebut Harbert's story that, after a few drinks at a business meeting, he thought he'd hit a deer while driving home?
The evidence that proved crucial to convicting Harbert of charges, which included failure to stop and render aid, came from the defendant's own computer. A forensic examination of his hard drive revealed numerous suspicious Google searches within a few days of the accident, including such terms as "auto glass reporting requirements to law enforcement," "auto glass, Las Vegas," "auto parts," "auto theft," as well as web pages for the local police department and a news site that covered Kaur's death.
Although he was convicted and sentenced to a three-year prison term, Harbert appealed, claiming that there was no evidence of any actual knowledge on his part that a human being had been hit.
On Jan. 14, 2009, a California appeals court upheld Harbert's conviction, holding that there was "abundant evidence" that the banker knew he had struck a person and ruling that Harbert's Internet searches were "inextricably linked to his state of knowledge" on the night in question.
On Jan. 16, 2005, Wendi Mae Davidson told the U.S. Air Force that her husband, Airman Michael Severance, had gone missing from their Texas home the day before. Investigators from both the Air Force and the San Angelo Police Department were suspicious; after all, their parallel investigations had both reached the conclusion that Severance wasn't the type to desert.
An Air Force investigator had learned that Davidson owned a horse, but didn't know the location of the ranch where it was kept until Air Force agents placed a GPS tracking device on her car. Data retrieved from the device led agents to a ranch owned by Terrell Sheen, who confirmed that he boarded horses including Davidson's.
Sheen gave them permission to search the property, which included not just a barn and fenced corrals but also ponds. Although an initial search turned up no sign of Severance, a few days later a Texas Ranger and a San Angelo detective interviewed Davidson at the veterinary clinic where she worked.
At some point in the case, investigators had examined Davidson's computer, and discovered that it had been used to perform Internet searches for some rather curious topics, including polygraphs and "decomposition of a body in water."
When questioned about her interest in such unusual topics, police said that Davidson became defensive. Not surprisingly, after this Michael Severance's body was found in one of the ponds on the Sheen ranch.
He had apparently been poisoned with a concoction of animal sedatives (something Davidson clearly had access to) and then dumped into the pond, his body weighed down with a boat anchor. Wendi Mae Davidson was sentenced to 25 years in prison; although she later challenged both the search of her computer and the tracking of her car on appeal, her conviction was upheld.
Wendi Mae Davidson's case was certainly not the last to rely on evidence from Internet search results.
In February 2010, a California appeals court upheld the murder conviction of Manuel Mares. Back in October 2006, Alia Ansari was walking with her 4-year-old daughter in Fremont, Calif., when witnesses heard a gunshot-like noise, and then saw a man run to a black Toyota and speed off, leaving Ansari dead with a gunshot wound to the face.
Police stopped a car matching the witnesses' description within a half mile of the crime scene, minutes after the shooting; the driver of that car was Michael Mares. Although they found gunshot residue and other physical evidence, police could not find a gun, a silencer, or any ammunition.
But Mares left a trail of digital footprints. A forensic examination of his computer revealed web searches containing phrases like "firearms," "make silencer," "homemade silencer," "how to make silencer," "anarchist cookbook," and others.
Mares also apparently visited a website showing how to make a disposable silencer, as well as a site marketing DVDs of grisly death scenes.
Mares was convicted and sentenced to 53 years to life for first degree murder.
Although he claimed on appeal that allowing evidence from his Internet searches was unfairly prejudicial, the California Court of Appeals disagreed.
It upheld the conviction, reasoning that the "defendant's Internet searches for silencers in the weeks before the killing were pertinent to his state of mind regarding premeditation and deliberation, and evidence of the searches was properly admitted."
Results from Internet searches can seemingly speak volumes on behalf of a murder victim. Consider the case of Julie Jensen, found dead of ethylene glycol poisoning on Dec. 3, 1998, in Kenosha County, Wisc.
Julie's husband, Mark Jensen, initially told police that he thought she'd had an allergic reaction to some medication she was taking. But when police detectives began piecing together the evidence, it added up to murder.
It seems that—disturbed by changes in her husband's behavior, such as trying to get her to drink wine and "looking at strange material on the Internet"—Julie Jensen had written a note to a neighbor with instructions to give it to the police if anything happened to her.
In the note, Julie detailed her fears that her husband was reading computer pages about poisoning, behaving strangely, and that he might be trying to kill her.
Police examined the Jensens' home computer. On it, they found Internet searches for botulism, poisoning, pipe bombs, and even a visit to a website that explained how to reverse the polarity of a swimming pool by switching the wires around.
Most damning were searches for "ethylene glycol poisoning" (ethylene glycol is an ingredient found in antifreeze), coupled with the fact that, on the morning of Julie's death, someone had tried to "double-delete" the computer's browsing history—unsuccessfully.
In addition, at trial a co-worker of Mark Jensen's testified about Jensen's boast that giving someone doses of Benadryl and antifreeze over an extended period of time would not only kill the person, but be "undetectable."
In 2008, Jensen was found guilty of first-degree homicide. He appealed, claiming that the warrantless police search of his computer violated his constitutional rights.
Noting that Jensen had signed a consent form, the Wisconsin Court of Appeals rejected his arguments and upheld his conviction on Dec. 29.
What you say can and will be used against you. But even when you say nothing, your computer search history can say it for you.