Identification

Blender

Detective Katherin Corona receives the blender from the house and finds no fingerprints, but there's a hair captured in the base.  It has been pulled out from its root, and the degradation of the follicle suggests that it was pulled less than 24 hours ago.   She sends the hair to DNA for identification.

Blister packs

After looking for a match, Detective Corona finds that the fingerprints in the blister packs have two sets.   One belonging to Susan, and the other belonging to Mrs. Shepard.   The fingerprints on the K-Dur packs belong ONLY to Mrs. Shepard.  Susan never touched them.

Drugstore invoices

In the inspection of the garbage containers, some invoices were found for the purchase of K-Dur tablets.  Apparently the blister packs found were all new.    They have been charged to Daniel Shepard's credit card.

Susan

Susan Potter, 28 years old. She is the deceased’s private assistant. Beautiful, young and smart. She works to support her sick mother who suffers from glomerular disease. She had recently been seen with Daniel Shephard at a  new nightclub famous for its high-spending customers. Jonathan was very upset about it. He threatened to fire her, but he didn’t.

Mrs. Shepard's background

In the past, Lindsay McDermott used to work as a Medical sales representative, selling products for a particular laboratory.   While working on that area, she met her first husband, Tom Lynn.  They were married for two years, until he died of a heart attack 26 years ago.  He had kidney problems.   Later on, she moved to another state, where she met Adrian Lafayette, a kidney patient too.    They got married and three years later he had a heart attack and died.   In both cases, the husbands had had no children, so the inheritances had all been for her.   Ten years ago she was working again as a Medical Sales Representative, and she met Johnathan Shepard.  They got engaged very quickly, and got married after six months of dating.
Susan says she found out about Mr. Shepard's sons and daughter after the engagement, and this produced a terrible argument between them.   

Apparently Mr. Shepard's children visited less and less often.

Later on, the detective found that Logan Hatfield had also worked as the legal attorney for Mr. Lafayette and Mr. Lynn.