Updated

A University of Georgia professor who killed his wife and two others before fleeing was targeting her male friend, authorities said Tuesday.

George Zinkhan, 57, and wife Marie Bruce had been having marital problems at the time of the April 25 shooting spree.

Zinkhan, a marketing professor at the University of Georgia's Atlanta campus, was specifically targeting a Clemson University economist who volunteered with Bruce, 47, at the local theater group.

Authorities said Zinkhan fired at Tom Tanner, 40, first before aiming at Bruce. The exact nature of the relationship between Bruce and Tanner wasn't immediately clear.

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Zinkhan vanished after the murders, leading authorities on an international manhunt. His body was found Saturday near his home in a grave he dug himself and police said he died from a self-inflicted gunshot wound to the head.

Authorities said Zinkhan used a shovel to carve a hole and then dumped dirt and debris on himself before shooting himself in the head with a handgun. He left no suicide note.

A gray sports bag with his clothes and another gun were found at his side.

Jim Fullington, 63, with the Georgia Bureau of Investigation said the third victim, Ben Teague, was "at the wrong place, at the wrong time."

All three victims died at the scene.

Police found his body on Saturday, two weeks after the shootings, in a self-dug grave in the woods not far from his home. The discovery was made near where Zinkhan's partially wrecked Jeep was located in a ravine.

After the killings, Zinkhan dropped the couple's two children off at a neighbor's house. Police said they're now with relatives in Augusta, Ga.

Zinkhan had been dead between five and 14 days before his body was discovered, according to authorities, but they don't believe he was in the woods for long before he committed suicide.

Police have not released a motive in the killings, but Fullington said Zinkhan was having "marital difficulties" and getting marriage counseling.

All three victims were members of a local theater group gathered that day for a reunion at the Athens Community Theater, a short distance from the University of Georgia campus where Zinkhan taught.

Fullington said Zinkhan targeted Tanner first, though he would not say why.

Authorities believe Zinkhan left his two young children in the car during the shootings. He was last seen dropping them off at a neighbor's house soon after, saying there was an emergency.

Bulletins were issued nationwide and authorities kept watch on airports in case Zinkhan tried to flee to Amsterdam, where he has taught part-time at a university since 2007.

Nearly a week after the shootings, police found his passport and his wrecked Jeep in a ravine in a wooded area near his house on the outskirts of Athens, a college town 70 miles northeast of Atlanta.

Hundreds of law enforcement officers scoured the area for days but it wasn't until Saturday that a team of cadaver dogs found his body hidden in a small dug-out area about 15 inches deep.

"It was apparent he had taken significant steps to make sure his body wasn't located," said Major Mark Sizemore of the Athens-Clarke County Police Department.

In his abandoned Jeep, authorities found Zinkhan's cell phone, laptop, wallet and a map to the home of Barbara Carroll, a fellow University of Georgia professor. Sizemore said the map had been printed the day before the shooting.

Carroll told her colleagues in an e-mail obtained by The Red & Black, the UGA student newspaper, that she believes Zinkhan planned to kill her too.

Zinkhan had been a professor in the university's Terry College of Business and had no disciplinary problems, school officials said. He had taught at UGA since the 1990s and was fired after the shootings.

He'd shown signs that he may have been looking to leave Athens. In March, he interviewed for a position in the University of Alabama's business school but was not offered the job, said school spokeswoman Cathy Andreen.

Authorities said many of the mysteries surrounding the shooting may never be solved.

"There are some questions that we will never know the answer to," Sizemore said.

Click here for the 911 call transcripts.

Click here for more on the story from MyFOXAtlanta.com.

The Associated Press contributed to this report.