A police car and hazmat semi-trailer sit inside the The Village Bend East apartment October 16, 2014 in Dallas, Texas. (Photo by Mike Stone/Getty Images)

A 29-year-old mother reportedly warned a close friend that if she ever disappeared, to look no further than her husband to start piecing the puzzle together.

Now, Air Force Major Andre McDonald has been arrested on suspicion of killing his missing wife.

According to court documents, McDonald tried to hide evidence of his alleged crime; the purchase of an ax, a shovel, two 5-gallon containers of gasoline and a burn barrel, PEOPLE reports, all items that authorities say could be “used to dispose of the body” of Andreen Nicole McDonald.

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“We believe that Andreen McDonald is no longer living,” Bexar County, Texas, Sheriff Javier Salazar told reporters Sunday after the arrest of her 40-year-old husband who was hit with an evidence tampering charge.

The victim was the mother of the couple’s 6-year-old daughter, and she had been missing since Friday. Her family and friends became alarmed when she didn’t show up to work or the gym. Her friends even went to the family’s home in San Antonio and spoke with her husband, but when they “weren’t able to get many answers,” they contacted the sheriff’s office, said Salazar at a Saturday press conference, the San Antonio Express-News reports.

When officers attempted to question McDonald on Friday about his wife’s possible disappearance, he opted to exercise his right to remain silent and “lawyered up pretty quick,” Salazar said.

The sheriff noted that McDonald’s demeanor immediately raised red flags.

“Not the fact that he asserted his rights,” he said. “The fact that he didn’t seem to care very much at all that his wife was missing and the fact that he just flat out refused to help us find her.

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Investigators became concerned with McDonald’s mental health after he was observed by a surveillance team purchasing a gun and ammunition, but he quickly left the store leaving both along with his identification behind.

He was placed in custody for a psyche observation; after which officers obtained a search warrant for the couple’s house. On Saturday night, officials uncovered possible evidence,  including blood “in plain view,” said Salazar.

They also reportedly recovered a torn sales receipt for the ax, shovel, gasoline, burn barrel and trash bags, which authorities suspect “were implements that were going to be used to dispose of the body,” said the sheriff.

“There was quite a bit of effort that went into destroying that receipt to try to prevent us seeing where it was purchased and when it was purchased,” Salazar alleged. “That led us to obtain a warrant of arrest for Andre McDonald for the charge of tampering with evidence.”

McDonald has not been charged with his wife’s disappearance or murder, although he is the prime suspect, according to an arrest affidavit.

He was booked into the Bexar County Jail and his bail set at $2 million.