SPRING, Texas -

Fifty-four-year-old Mark Desper Gideon has been charged with capital murder in the deaths of his mother and sister.

Gideon was arrested Friday evening near the intersection of Herald Avenue and McCarty Drive in east Houston Friday evening.

Gideon was a person of interest in the deaths of his 75-year-old mother, Margaret Gideon, and his sister, 52-year-old Vonda Gideon. Vonda and Margaret's bodies were found inside their home Thursday in the 9200 block of Kirkleigh. Detectives said the women both suffered trauma to the head.

Investigators said they recovered new evidence in the deaths of a mother and daughter found inside a Spring home. The Harris County Sheriff's Office said they found Vonda Gideon's missing truck.

Robert Hughes knew Margaret and Vonda as tenants and friends. When a neighbor hadn't seen the women for a week he alerted her friends. Hughes was the first to stop by the home. With a strong odor coming from inside, Hughes said he knew something was wrong so he dialed 911.

Hughes called Vonda a devoted daughter who cared for her sick mother.

"My wife and I will miss her," said Hughes. "She was a really nice person and it's sad to see her come to this end.  I know things weren't always easy for them because the mother was ill, quite ill, in a chair."

Investigators said Vonda's work truck from her job as a ReMax realty agent was missing and so was her brother, Mark. While deputies have now found the truck, the search continues for Mark.

Deputies said when Mark Gideon didn't live with his mother and sister, he often lived on the streets.

Neighbors wait for answers and recount their past dealings with Mark Gideon.

"A few times he would come over and visit with me, but very briefly," said neighbor Glen Bedingfield. "He seemed to be a little spacey."