SPRINGFIELD, Ill. (WAND) - After months of investigation, authorities still have no clear motive for the Bunn-O-Matic warehouse shooting from June, but they have concluded the victims who lost their lives were targeted. 

Police said on June 26, the shooter, Michael Collins, was seen walking past other employees straight towards two of the three victims who were shot and killed.

Collins, 48, worked at Bunn-O-Matic for 22 years prior to the shooting and had a few minor infractions. However, police said nothing would have indicated he planned to shoot and kill coworkers before fleeing police and killing himself.

Police were denied access to Collins' medical and financial records by a judge, but they said medications for anxiety and depression were found in his system.

Police said Christopher Aumiller and Bill Gibbons were the targeted victims. They worked in the same area as the suspect.

The third victim, Marsha Strumpher, was able to escape the building and call 911. However, as the suspect left the building, police said he went to his vehicle, came back, and shot and killed her as she talked with other people who had escaped the building.

At the start of Friday's press conference, police played 911 calls made from witnesses at the warehouse, including the call made by Strumpher before she was shot and killed.

Police conducted more than 200 interviews, including over 100 Bunn-O-Matic employees.

Authorities said Collins used two handguns in the attack.

"We will work diligently and exhaust all leads and efforts to provide answers to the victims' families, but in the end, we may not be able to," Springfield Police Chief Kenny Winslow said.  

In a Wednesday press conference, Winslow said their investigation into the shooting revealed Collins walked up to Aumiller and Gibbons and shot them in close proximity at their work stations.

Collins left the scene in his vehicle after shooting Strumpher in the parking lot. Morgan County authorities later found him dead in his vehicle. Police said he had shot himself.

"We believe he is the lone suspect," Winslow said. "We don't believe he worked in conjunction with anyone else. We believe he is the lone suspect."

Police went on to say they have recovered a tablet and a phone connected to Collins, but they are searching for a second phone that they believe may hold more information about the shooting. They referred to it as the "missing piece."

Collins had a valid FOID card and purchased the guns used in the shooting at a local sporting goods store. One gun was used on Aumiller and Gibbons, while the other was used on Strumpher.

Some of Strumpher's family were present at Friday's press conference.

Bill Gibbons sister, Connie Gibbons, sent WAND a statement saying, "I miss him and love him so much that I feel like I've died inside. I have good... some happy times where I can hear him  yelling at me to stop crying, moments that I can feel him around me. I love my family and friends and tell them everyday, because now I live with the fear it could happen to any of us at any time.  The world we are currently living in is full of hatred , violence and evil. The only hope we have is God's mercy. When it's time, it's time.