LOUISVILLE, Ky. (WHAS11) -- The 2011 murder of 14-year-old Trey Zwicker wouldn't be officially solved until 2013 when his step-father, Joshua Gouker, admitted to beating the teenager to death and leaving his body behind Louisville's Liberty High School.

Gouker is currently serving a life sentence after entering a plea deal.

But, Zwicker's father, Terry, believes there were signs of Gouker's violent behavior before the murder.

Court documents show Gouker was involved in several domestic violence cases and was sentenced to five years in prison for robbery in 2004.

VIDEO: REMEMBERING TREY ZWICKER

In 2013, Gouker was also convicted of animal torture for killing Trey's dog. It's that behavior, Terry believes, that should have been a red flag.

"If you are willing to do this to an animal, in my opinion, it's just a start before you start doing it to a human being and people need to look at that," said Zwicker.

Kentucky Representative Walker Thomas is looking into creating harsher penalties for people convicted of animal torture and domestic violence.

The Battered Women's Justice Project reports up to 71 percent of domestic violence victims report their abusers also threatened, injured or killed a pet.

Rep. Thomas says there is a clear link between animal abuse and domestic violence so next year, he plans to put forth legislation that would automatically make it a class D felony (punishable of up to one to five years in prison) for those convicted of animal abuse - while also requiring their sentence not be suspended, probated or conditionally discharged if the person also threatened, harassed or terrorized a family member or someone in a dating relationship.

â–ºContact reporter Robert Bradfield at rbradfield@whas11.com. Follow him on Twitter (@RobertBreports) and Facebook.

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