For decades after the BTK strangler (search) wiped out half of his family, Charlie Otero said he lay low, fearful that the serial killer — who has recently renewed his cat-and-mouse game with investigators — might be watching.

"I didn't want him tracking me, knowing where I am," Otero said in a telephone interview Tuesday from the Western New Mexico Correctional Facility, where he is nearing the end of a four-year sentence for aggravated battery in a domestic violence case.

"No rent, no house, no bills," he said. "Nothing. No jobs. No checks."

Now 46, Otero remains convinced his father knew the killer because he had been acting strangely to protect the family in the days just before the killings. And he believes his family was targeted because of something his father did during his military service.

"I've always thought my father knew him, that is about all," Otero said.

Otero was 15 when he found his parents' bound bodies in their bedroom in 1974. Police told him later that his brother and sister were also killed — the earliest deaths claimed by the killer.

Wichita police declined Wednesday to talk about Otero's comments, saying discussing specifics outside of previous statements released at news conferences could jeopardize their investigation.

But Brian Reshetnik, deputy warden at the New Mexico prison where Otero is incarcerated, said Wednesday that Otero spoke by phone Tuesday night with a Wichita police detective about something that had jogged his memory in the case. Otero has been corresponding with police for the last six to eight weeks, he said.

Otero said he wants to help in the case is any way he can. "I've had this bottled up inside me for 30 years," he said.

On Jan. 15, 1974, the three surviving children of Joseph and Julie Otero (search) came home from school to find their parents and two other siblings, Josephine, 11, and Joseph II, 9, dead at the family's Wichita home.

His father knew something was wrong, Otero said, citing several instances in the days before the murders that were "very suspicious." One time when the power went out, his father made the family get into a closet until he made sure the neighborhood was also dark.

Another time, when a telephone repairman showed up at the house, Joseph Otero made his son go to a window to make sure there was a company van there before he opened the door.

Just days before he was killed, Joseph Otero, who worked as an aircraft mechanic, tried to give his son his ring — in case something happened to him.

"Nobody hated my family," Otero said. "I am sure it had something to do with my father's military history. My dad did things. ... He had to tell somebody what he had been up to in the last few years and he was dead days later."

Otero said an overheard telephone conversation his father had days before his death is the reason for his belief in a military connection. He said his father was involved with the Inter-American Air Forces Academy (search), a program that has trained Air Force personnel from Latin America for 60 years.

BTK, the killer's self-coined nickname, stands for "Bind, Torture, Kill." He has been linked to eight unsolved homicides that terrorized Wichita between 1974 and 1986. After years of silence, the killer resurfaced by sending letters to police and media this year.

Attention refocused on BTK in March, when The Wichita Eagle received a letter with information on an unsolved 1986 killing. The letter contained a copy of the victim's driver's license and photos of her body.

It was the first communication from the killer since the late 1970s, and police said it linked the serial killer to the 1986 slaying. The other seven slayings were in the 1970s, with BTK claiming responsibility for those deaths in letters to the Eagle and a television station.

Police have received thousands of tips from the public since March.

On Tuesday, police released a summary of personal details provided in recent letters they believe were sent by the killer, including scattered facts about his life.

He suggested he was born in 1939, lost his father in World War II and is a railroad buff. The statement did not say where he was born or where he lived, but that his family moved frequently and always lived near railroad tracks.