CIBOLO, Texas -

Cibolo police have determined the deaths of a man and his older sister were the result of a murder-suicide.

Police said 51-year-old Keith Tanner beat his 68-year-old sister, Patricia Peek, to death before shooting himself in the chest.

Their bodies were discovered on Monday.

Investigators say Tanner sent a Fed-Ex package to a relative that detailed plans to kill himself.

That relative received the package after the deaths.

Tanner recently lost his job, but so far, there's no indication of why he would kill his sister.

Investigators are searching his home in Austin trying to get more information.