LUBBOCK, Texas — On Friday, Rey Martinez, a former lead investigator with Lubbock Police Department, recalled the events following the murder of Tammy Cooper and her three children on Oct. 25, 2004.

“It was a typical day,” Martinez said.

Martinez received the news of a family who had been killed.

“At first you know, I was thinking it was carbon monoxide poisoning or something,” Martinez said.

Not long after, however, he walked into the crime scene, and found a family of four brutally murdered. Tammy Cooper and her children, Mahogany, Kasheim and KaDiece Allen, stabbed and beaten to death.

“It was like walking into a nightmare,” Martinez said. “Shocking, even for veteran homicide investigators.”

He said he thinks about the case every day.

Martinez said he believes Tammy knew her killer. The killer stopped at her home around 11 p.m. on October 24, and police obtained a phone call made right before the murders. Tammy is heard describing him to a friend, saying he was a black man going by the name of ‘Butch.’ She tells her friend he isn’t from the area, but allows him into her home.

“It generated some information and people we might need to talk to and things to look at,” Martinez said about the phone call.

The case faced other obstacles, however.

“She was from the Dallas area and we obtained a lot of information about her and her life here in Lubbock, but she didn’t have a very big social network out here,” Martinez said. “Most of it was in Dallas, and it was very difficult.”

Martinez said investigators conducted interviews win Dallas, clearing potential suspects like Tammy’s boyfriend, who discovered the bodies.

Although Martinez is no longer with LPD, he still helps with the case.

“We’ve had a few meetings over this case recently,” Martinez said.

Martinez said anyone with information pertaining to the murder should call Crime Line. The number is 806-741-1000.