The year was 1971.  Neil LaFeve, an amiable but law-abiding game warden in Wisconsin was found murdered on September 24th, on his 32nd birthday.  That afternoon, he had been out in the woods posting signs and had planned to finish long before the party that his wife had organized for him.  When he failed to show up, his wife grew worried and phoned his boss.  They discussed it together, but there was no reason they could think of that Neil might still be out in the woods. 

LaFeve's boss drove out to have a look.  He noticed that all the signs had been posted, so when darkness came and there was still no indication that LaFeve was returning, he called the police.  They searched through the night, but gave up without finding the missing warden. 

In the morning, the search party came across LaFeve's truck.  It was empty and the door was ajar. Things looked bad and only got worse when they found a large amount of blood not far away.  Another searcher picked up some broken sunglasses and two spent shells from a .22 rifle.  From there, more signs of a wounded man formed a trail: human body matter, a tooth, blood, and bone fragments.  They felt certain they would not find him alive.

Finally the search party reached a spot that looked like it had been recently dug up.  The police got shovels and soon they had located Neil LaFeve - without his head.  Another freshly dug spot nearby, though much smaller, yielded his head.  It had been hacked off with a blunt instrument---a shovel or spade---and two bullets were imbedded in the skull.  The coroner also found several bullets in the corpse.

The first step was to determine if LaFeve had any enemies.  The officers in charge of the investigation looked through a list of men that LaFeve had arrested for poaching, because these men could have a vendetta.  The brutality of the attack indicated rage or revenge, not just a random killing. 

All of the men who had been convicted of hunting illegally on those grounds were located and interviewed on tape, and a few were asked to submit to polygraph exams.  However, there was one man who refused to cooperate: 21-year-old Brian Hussong.  LaFeve had arrested him several times, yet he had continued to poach.  Hussong had no alibi for September 24th and he resisted all attempts to clear up the murder mystery.  He seemed a likely suspect.

Sergeant Marvin Gerlikovski was in charge, so he got a rare court order that allowed him to put a wiretap on Hussong's house.  He took the extra precaution of recording everything that was said, which paid off in a way he didn't expect. 

It wasn't long before Hussong got on the phone to get his grandmother to hide his guns and give him an alibi.  She appeared to cooperate, so Gerlikovski sent detectives to her house.  Flustered, she led them straight to the hiding place.  Ballistics experts confirmed a match between the .22 rifle and the bullets found in LaFeve's body, which was enough evidence to place Hussong under arrest. 

Gerlikovski then sent the tapes he had made to Michigan's Voice Identification Unit—at that time the best in the world for this type of procedure.  The leading experts in voiceprint analysis had trained these officers.  Ernest Nash examined the tapes, gave his opinion, and ended up serving as an expert witness during Hussong's trial.  However, it was not Hussong's voice that he testified about, but that of Hussong's grandmother.  She had denied saying that she had hidden the guns, so Nash explained how he could match her voice to that of the voice on the tape.  He then used his laboratory results to affirm that she was definitely the person speaking to her grandson on the tape.

The jury listened to the tapes again, and after less than four hours of deliberation, they returned a guilty verdict of first-degree murder that gave Hussong a life term in prison.

So just what is it about the human voice that makes it electronically measurable?