Edward F. Bachner IV, of Lake in the Hills, was trying to cash in on his wife's $20 million life insurance policy, WBBM, Chicago, reported.
Bachner was arrested in July 2008 after the FBI found he had been buying the puffer fish poison, tetrodotoxin, from the biochemical manufacturing firm Biotium under the name Dr. Edmund Backer of EB Strategic Research.
Biotium sent Bachner 64 milligrams of tetrodotoxin in four separate shipments to a post office. Bachner ordered a fifth shipment from another biotech firm, Ascent Scientific, for 98 mg.
The fatality rate of ingesting tetrodotoxin is 50 to 60 percent; 1 to 2 mg can be lethal.
It took FBI agents and hazardous materials teams two days to search Bachner's house for the poison when the man was arrested.
Bachner had previously been investigated in an alleged murder for hire plot but there was not enough evidence to charge him in that case.
No sentencing date for Bachner was reported.