LA CROSSE, Wis. -

Jeffrey Lepsch of Minnesota is set to go to trial Tuesday.

He's accused of shooting Paul and his son A.J. Petras to death in their downtown La Crosse family business last September.

Lepsch has been charged with two counts of first-degree homicide, armed robbery and possession of a firearm

Paul and A.J.'s death sent shock waves through our community.

With just a day before the trial begins, one family friend is hoping to find the answer to a question that still remains -- why did this have to happen.

“I drive by Paul's house at least twice a day,” said Ted Withey, Paul’s best friend. “So, I'm always thinking of him.”

September 15, 2012 is a day Withey can never forget.

“Paul was probably one of my best friends here in La Crosse,” said Withey. “It's hard for me to not remember the details of something like a tragedy like this. It's always in your mind.”

Withey walked down to May's Photo in Downtown La Crosse that night to see it surrounded by caution tape and police cars.

La Crosse police were investigating a shooting.

“It was really gut-wrenching,” Capt. Robert Lawrence of the La Crosse Police Department said last September. “It was something that really took me aback, that we have another homicide that we are investigating.”

Inside May’s Photo, Paul Petras's body was found in the restroom and his son A.J.'s body in front of a safe behind the main counter.

Thousands of dollars worth of camera equipment was also missing.

What happened was something Withey still can't come to terms with today.

“Killing two people over 20 some thousand dollars of camera equipment just doesn't make any sense,” said Withey.

Days then turned into weeks as police continued to investigate hundreds of pieces of evidence as well as hours of surveillance video collected from nearby downtown stores.

“From the pure investigative angle, we knew to a certain level it was to our advantage that it happened in that area, and we would be able to get some video from the area,” Capt. Jason Melby of the La Crosse Police Department said last October. “There was the possibility of multiple people who could have seen this individual or help us develop a description.”

Then Oct. 11, 2012, more than a month after Paul and A.J. were killed, police arrested Jeffrey Lepsch of Dakota, Minn.

Police said surveillance video caught a man police believe to be Lepsch, wearing a gray-hooded sweatshirt and a backpack getting out of a van and going inside May's Photo just before 2 p.m. that day.

He left an hour later carrying four bags.

Investigators also tracked down the blue Dodge Caravan caught on security video. The van belonged to Lepsch's wife.

After searching their Dakota, Minn. home, police found 14 of the missing pieces of camera equipment and a gray-hooded sweatshirt inside.

Now as Lepsch's trial is set to begin, Withey hopes one question can finally be answered.

“We all want to know the bottom line, and the bottom line is what did happen,” said Withey.