Michelle Warner's boyfriend taped Dr. Phil interview before allegedly confessing to her murder

Mark Castellano in court on Tuesday, Oct. 2, 2012 KHOU

(CBS/AP) HOUSTON - Mark Augustin Castellano, who is accused of killing ex-girlfriend Michelle Warner and then driving hundreds of miles to dump her body in a West Texas oil field, taped an interview about the case with the "Dr. Phil" show two days before confessing to investigators, police said Monday.

PICTURES: Body of missing Texas mom found

The 37-year-old computer technician has been charged with murder in Warner's death. During a two-hour interview, Castellano told investigators he killed Warner after an argument in their apartment on Sept. 22, in which he grabbed her by the throat and apparently snapped her neck, said Houston Det. Fil Waters.

Warner's family reported her missing several days later.

Waters said Castellano initially told investigators that Warner had run out on him and their 3-year-old son. Castellano, who was staying with his son at his parents' home in Odessa in West Texas, kept in contact with police duringthe investigation into Warner's disappearance, and agreed to return to Houston on Sunday to speak with investigators.

Waters said Castellano also indicated he had taped an interview for the "Dr. Phil" show on Friday.

"I thought he was kidding, but it was the real deal," Waters said. "He talks to Dr. Phil, provides Dr. Phil as I understand it, with the same information he's been providing everyone else."

In a brief statement, Stacey Luchs, a spokeswoman for the "Dr. Phil" show said, "Mr. Castellano sat down for an interview with Dr. Phil in Texas just before his confession to law enforcement, late last week. Dr. Phil also conducted an interview with Ms. Warner's family for this show, which is currently scheduled to air on Thursday."

The statement did not say what Castellano talked about during his interview.

Castellano appeared in a probable cause court early Tuesday, reports CBS affiliate KHOU. He is being held on $150,000 bond.

More on CrimesiderOctober 1, 2012 - Michelle Warner: Body of missing Texas mother found after boyfriend confesses to her murder, police saySeptember 28, 2012 - Police search for missing Houston mother, Michelle Warner, 31