Edward F. Bachner IV has admitted to buying puffer fish toxin in hopes of killing his wife. (Credit: CBS)

CHICAGO (CBS) — A northwest suburban man has pleaded guilty to trying to kill his wife with poison from a puffer fish.

Edward F. Bachner IV, of Lake in the Hills, apparently wanted to collect $20 million on the life insurance policy for his wife, Rebecca Bachner.

The 2008 federal indictment against Bachner says starting in 2006, he used the alias of Dr. Edmund Backer of EB Strategic Research to purchase four different orders of the deadly puffer fish poison tetrodotoxin from the biochemical manufacturing firm Biotium.

The firm sent Bachner four shipments of tetrodotoxin to a Post Office box he used, totaling at least 64 mg in all.

He also ordered a fifth shipment for 98 mg of the poison from a second biotech firm, Ascent Scientific, which he received by claiming his name was “Dr. Backer” and wanted the tetrodotoxin for “marine antitoxin research purposes.”

Tetrodotoxin has a fatality rate of 50 to 60 percent, and has no known antidote. The Hong Kong Centre for Food Safety says 1 to 2 mg can of the poison can be lethal, and victims usually die within six hours of ingesting the substance.

Scientific researchers are legally allowed to purchase the poison, but must obtain special registration from the Centers for Disease Control and Prevention before trying to buy 100 mg or more.

In addition to buying the poison illegally, Bachner was also charged with making false claims to the Internal Revenue Service to take out the $20 million life insurance policy on his wife.

When Bachner was arrested in July 2008, FBI agents and hazardous materials teams spent two days combing through is home.

To their neighbors, Edward and Rebecca Bachner were known as members of the Vine Christian Church and led prayer groups that would meet in their home, CBS 2 reported in 2008.

But Bachner had been investigated in 2006 for an alleged murder for hire plot. The investigation was cut off due to a lack of evidence.

Bachner has been in federal custody for the past two years. His sentencing date was not immediately available.