CHARLOTTE, N.C. — The Charlotte-Mecklenburg Police Department is teaming up with ATF Charlotte to increase the reward money to $15,000 in the unsolved homicidal cases of a school teacher and another man. 

“We truly believe that someone out there has a piece of information that will be critical in bringing this case to a close," said Anthony Spottswood an ATF agent. "Because of that we are offering a $15,000 for any information leading to those responsible in the death of Ruijuan.” 

On September 9, 2016, at around 11:30 p.m., Charlotte-Mecklenburg police said 33-year old Ruijuan Guo was shot inside a parking garage in South End. 

“Rijuan was an innocent victim in this case, she didn’t know the person that shot her, but someone who was with her that night did,” CMPD Lt. Bryan Crum said.

Police say Guo was walking back to the car with her fiancé and a couple of friends, after leaving a concert down the block in South End. That’s when they were approached by several armed robbers.

“While Rijuan’s fiancé reached for his wallet, Rijuan was shot,” Lt. Crum said.

Guo died five days later on September 14. She taught Mandarin at Kensington Elementary School in Union County, after coming to the U.S. from China.

“Rijuan represented the best of what her country has to offer, and unfortunately she met the worst of ours,” Lt. Crum said.

Then came an unexpected twist between the time of the robbery and her death. 

Police say one of her friends who was with her during the robbery, Joe Fuqua, was also murdered.  According to investigators, Fuqua was a suspect in Guo’s murder, though he did not believe it would lead to murder.

CMPD detectives believe these two cases are connected. Police said Fuqua was a suspect in Guo’s death but detectives believe he was not the one who shot her. 

“Joe was a suspect in Rijuan’s homicide, Joe did not kill Rijuan," Lt. Crum said. "He did participate in the planning of the robbery that ultimately led to her death."

CMPD said they believe Fuqua was killed because he knew who killed Guo. Police are now urging anyone with information regarding this case to call police immediately. 

“We truly believe there is somebody out there that has a piece of information that will be critical to bringing this case to a close,” said Anthony Spotswood, ATF supervisory special agent.

Anyone with any information is asked to call 704-432-TIPS. Police said you can remain anonymous. 

“It’s incredibly important that they step forward and do the right thing and help us out,” Lt. Crum said.

CMPD says they did arrest a suspect in the murder of Fuqua, but he has not been cooperative with the investigation.

CMPD released a video of an interview with Guo’s fiancé, Nathan Beardsley.

“She was taken from us, it wasn’t some sort of accident,” Beardsley said in the CMPD video.

Beardsley said he didn't think he'd ever meet anybody like Guo again. 

“These people need to be caught and they need to be punished, they shouldn’t be out walking around enjoying their lives,” Beardsley said in the video.

RELATED: Autopsy of slain Union Co. teacher released

RELATED: Kensington Elementary teacher dies after being shot by robber