 When alerted to the possibility of Michael Farrar having been poisoned in the months before the fire , detectives investigated the origin of the castor beans that had led to police investigating the September domestic dispute . The label on the seed packets identified them as a product of the Earl May chain of stores . An officer found contact information for the Olathe , Kansas Earl May store in Green 's address book . The detectives contacted nearby Earl May stores to find if any employees remembered selling castor beans , which are out of season in the fall . A clerk in Missouri recalled that in September a woman had ordered ten packets of the out @-@ of @-@ season seeds and explained that she needed them for schoolwork . The clerk gave a description of the buyer that corresponded to Green , and tentatively identified her in a photo line @-@ up as the buyer . Register tapes in the store 's records showed that a purchase price corresponding to ten packets of castor beans had been rung up on either September 20 or 22 . No records were found in any Earl May store of earlier such purchases that would have corresponded to Farrar first having become ill earlier in the year . 
