Complicated Case: Heir

Young Contractors Benjamin Firth received an inheritance from a Mr. Jeremy Nout. That same night, burned the barn Mr. Nout. According to the investigation into the fire burns and the owner himself. This is evidenced by found bones and pants with buckle Mr. Jeremy Nout. According to preliminary data of the investigation becomes the prime suspect Benjamin Firth, 33-year-old contractor from Northwood.
From the testimony of the accused:
,, 14th of this month to my office granted Mr. Jeremy Nout. He introduced himself as an old friend of the family. Then he told me that he was old, and since he had no family, all his inheritance he wants to give me, Benjamin Firth. Asked about his visit is not to tell the parents as it will be a surprise. Then we agreed to meet at his house the next day to discuss the details of the will.
I went to Mr. Nout in 22.50, was opened by a maid and held in the office of the owner. After reviewing all the papers and sign the will, it was about 2 am the master Nout so as not to wake the maid led me through the backyard and I went to sleep in the hotel << Golden Shoe >> . In the morning, I found out about the incident.

P.S. Departing from Mr. Jeremy Nout I scored him his cane.
Why kill the heir to his benefactor ????