Wood said he was given a police bodyguard, and that other staff members were receiving protection.
McLelland began regularly carrying a gun following Hasse's murder in January. He had sworn at Hasse's funeral that he would track down the person or people responsible for his death.
Sources told ABC News affiliate WFAA-TV in Dallas that a police officer friend went to check on the McLelland's Saturday night and found the front door of their home open. When he walked inside, the sources said, the officer discovered Cynthia McLelland dead in a front room of the house and Mike McLelland dead in a hallway, as though he had tried to escape the assailant.
Neighbors were left shaken by the acts of violence.
"We've lived here for years and we've never had anything like this happen before and for it to happen so close to home is very, very scary," neighbor Vanessa Hernandez said.
The task force created to investigate Hasse's murder was also at McLellands' home, police said.
ABC News' Alexis Shaw, Gina Sunseri and Pierre Thomas contributed to this report.