My murderer

In Stage 2: Module 1 of the Creative Writing Course, I developed the character that is going to be murdered in my novel. The Creative Writing Course is now finished, and I am working hard on my novel.
   This week, I worked on developing my characters. I developed my main character and his love interest, his parents and his siblings. I also developed my murderers.
   The novel I am writing is based on a historical murder: an unsolved murder. So, after doing some research on the many theories about who murdered Jim Barclay, I have decided to go with the most popular theory: he was murdered by cattle thieves.
   My cattle thieves are John "Jack" Beveridge and James Sidney "Sid" Beveridge. These brothers were the third and fifth children on five, born in Harrietville. They grew up with parents that were too busy for them, running a farm and a guesthouse at the gateway to the snow fields in Victoria. By the time Sid was born, his parents had absolutely no time for him. Jack became Sid's mentor. He idolised Jack, and tailed him everywhere. Jack was a cruel man. Harsh, unsympathetic and ruthless. He was strict on Sid and uncompromising. He beat Sid, called him names, put him down, and broke him. However, he would not let anyone else talk down to Sid, and would not let Sid put up with anyone talking down to him. He would set Sid on people, like a fighting dog. Jack dominated Sid completely.
   Jack worked in a gold mine, saving money to buy a farm. In the early 1900s, he bought a farm at the top of the Buckland valley, with cattle lease rights including the Barry Mountains and Tea Tree Range. Sid and Ada went to live with him, and work for him. Jack would buy cheap cattle all over Victoria, and he would send Sid to collect. Sid became an excellent cattleman, and would steal extra cattle when he was driving Jack's cattle home.
   Sid had no idea of what was right or wrong. He took what he wanted, and wasn't pulled up by anyone because they were scared of him. Sid was scared of no one except for Jack. He was a fighter. Jack wouldn't berate Sid for stealing, because to contributed to his own wealth. Sid often stole to give a gift to Jack.
   Sid was simple. He wasn't interested in anything but making Jack happy, and cattle. He loved cattle. He dreamt about cattle. He loved the calves, how they played, and how they wagged their tails when they drank from their mother. He hated weaning the calves, which he always thought was done too early. He hated selling them, but Jack would hit him over the back of the head and sell them anyway.
   They drank a lot. They never married. They kept their sister like a maid.
   They wanted Jim Barclay's cattle, which were fine cattle and worth a lot. Jack set Sid to kill Jim, and they stole all the cattle. Conveniently, Jim Barclay and Jack Beveridge shared the same initials, so Jack sold the cattle as if they were his own. He got very rich and bought up land all over north-east Victoria.
   Sid was never concerned about being caught. It never crossed his mind that what he had done was wrong. If the police had ever suspected, and come asking questions, Jack would have dobbed Sid straight in and turned his back on his brother. But it never came to this.