INGRAM, Texas -- Authorities investigating the disappearance of a wealthy retiree have confirmed a body found buried in a Central Texas backyard is that of the missing man.

Now, the investigation into the death of 52-year-old Allan Kowalski has spread across three counties. Investigators say more charges are likely.

The retired investment banker was last seen Aug. 26 after having his picture taken for a dating service.

His body was found Thursday buried in a shallow grave near his three-story lake house after police arrested a man during a traffic stop who had tried to pass himself off as Kowalski. Officials determined Kowalski died after being shot several times in the head, Kerr County Sheriff Rusty Hierholzer said Friday.

Charles Lee Tidwell, a 46-year-old mechanic with a methamphetamine habit, was charged with Kowalski’s murder. Tidwell also faces charges of fraudulently possessing Kowalski’s identification information and of forging a government document.  Authorities say he inserted his photograph into Kowalski’s military ID.

Tidwell’s attorney did not return messages left by the San Antonio Express-News at his office.

Kowalski had befriended him and employed Tidwell to work on his classic cars. Kowalski even hired a lawyer to help Tidwell with legal troubles.

Tidwell had to undergo weekly drug tests as part of his probation. Kowalski offered to let the mechanic temporarily move in with him in Ingram, near San Antonio.

The wealthy retiree was “just an ace of a guy, really nice,” said Bob Galvan, a lawyer Kowalski had retained for Tidwell. “He was trying to help Tidwell and give him a leg up in life and then, well, obviously things turned bad.”

After Tidwell missed a court date, Galvan called to tell Kowalski. Worried he had put himself in a bad situation, the banker told Galvan he would kick out Tidwell if the employee didn’t shape up.

After Kowalski went missing, Tidwell and his wife took over the banker’s $500,000 home. Tidwell also invited two recently released felons, men authorities said are members of a white supremacist prison gang.

One of the men, Jeremiah McGregor, later told investigators they were all getting high when Tidwell told him he had killed Kowalski and buried him in the backyard, according to the sheriff’s office.

By the time sheriff’s deputies searched Kowalski’s house, it was practically bare. McGregor, 31, and Wayne Christiansen, 35, were charged with burglary in the case.