Investigators say it’s unclear what prompted an argument leading to the apparent murder-suicide of an Indiana couple just hours after their wedding over the weekend.

Vigo County Sheriff Greg Ewing said detectives have been interviewing wedding and reception guests of Kelly Ecker Samson, 50, and Dr. George Samson, 54, but have yet been unable to determine what caused the fatal dispute early Sunday following their Saturday evening nuptials.

“The investigation has revealed that there was a verbal argument between the couple toward the end of the reception, which carried over to the after-party at the couple’s home,” Vigo County Chief Deputy Sheriff Clark Cottom told the Indianapolis Star in an email. “Shortly after the last guest left at around 1:17 a.m., Kelly Ecker Samson called 911 reporting that her husband had threatened to kill her. There were a total of three very brief 911 calls, which in the first the caller disconnected.”

While on the phone, dispatchers reportedly heard what was thought to be multiple gunshots in the background. Police said George Samson, an anesthesiologist at a local hospital, shot his wife several times prior to fatally shooting himself once in the head with a .45-caliber handgun.

Ewing told the Tribune-Star that some guests told investigators the couple wasn't talking with each other, but Kelly Samson declined to leave the house.

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Vigo County Coroner Dr. Susan Amos told the Indianapolis Star that George Samson worked as an anesthesiologist at Union Hospital. He is also listed by the Bureau of Alcohol, Tobacco, Firearms and Explosives as a current federal firearms dealer.

Cottom did not specify what the newlyweds had been arguing about prior to the shootings, but the couple reportedly began bickering over their prenuptial agreement during their reception. The argument became increasingly heated as the celebration moved to the couple’s mansion in Terre Haute, reports.

"We're still gathering statements from the attendants," Cottom told the newspaper.

Investigators found 90 to 100 guns — including rifles, handguns, silencers and fully automatic weapons — and a store of ammunition in the house. Ewing said the guns have been seized for safekeeping for now.

The Associated Press contributed to this report.