Logan McQueary, father of missing baby Gabriel, testifies Monday in Elizabeth Johnson trial

PHOENIX - The father of a missing baby testified in a Phoenix court against his son's mother, Elizabeth Johnson, Monday.

Logan McQueary was the first witness to take the stand at the Maricopa County Superior Courthouse. Johnson is charged with kidnapping and custodial interference. Her baby, Gabriel, went missing nearly three years ago.

McQueary spent the morning telling jurors about his rocky on-again, off-again relationship with Johnson.

McQueary told the jury he broke up with Johnson in December of 2009, the same month Gabriel went missing.

McQueary said things eventually got so bad he started recording conversations he had with Johnson which included custody arguments about their son.

During testimony, prosecutors asked McQueary about a text message he received from Johnson on December 27.

"That's when I got the first text message from Elizabeth and the only thing she texted me was 'I killed him,'" McQueary told jurors.

After receiving the alarming text message, McQueary said he called Johnson, who had left Arizona, and questioned her.

"She told me that she had killed Gabriel and I said 'No, you didn't' and she said 'Yes, you made me,'" recalled McQueary.

Johnson later changed her story and said she gave Gabriel away to a couple in Texas.

Prosecutors argue that Johnson used Gabriel as a "pawn" in a game of revenge. It was a statement that caused Johnson to break down in tears last week.

Gabriel was 8-months-old when he went missing. He hasn't been seen since.