A professor who was believed to be making significant progress in his research of the coronavirus was found dead in Pennsylvania over the weekend. According to CNN, police said Bing Liu was shot and killed in an apparent murder-suicide at his home in Ross Township on Saturday.  

The 37-year-old University of Pittsburgh researcher was found with gunshot wounds to the head, neck, torso and extremities, police said. Investigators also found a second man who was found dead in his car outside of Liu's home.

According to the Pittsburgh Post-Gazette, the man was identified as 46-year-old Hao Gu, who is suspected of killing Liu before entering his car and taking his own life. Police didn't provide any additional information to confirm how they determined that Gu killed himself.  

Investigators said the two men may have known each other, but there is "zero indication that there was targeting due to (Liu) being Chinese."

"Bing was on the verge of making very significant findings toward understanding the cellular mechanisms that underlie SARS-CoV-2 infection and the cellular basis of the following complications," the professor's colleagues said in a statement to the Post-Gazette. 

Liu's co-workers also described him as "an outstanding and prolific researcher and an excellent mentor." The professor's colleagues vowed to continue his research "in an effort to pay homage to his scientific excellence."

"He was a very talented individual, extremely intelligent and hard-working," said Ivet Bahar, head of the computational and system biology department at the Pitt School of Medicine. 

Bahar said Liu "has been contributing to several scientific projects, publishing in high-profile journals."

"He was someone whom we all liked very much, a very gentle, very helpful, kind person, very generous," she said. "We are all shocked to learn what happened to him. This was very unexpected."

Investigators didn't disclose a motive for the killing, but they confirmed that nothing was stolen from the townhouse and there was no forced entry. Ross police Sgt. Brian Kohlhepp said Liu had the front and rear patio doors open at the time of the murder and his wife wasn't home. Police are still looking into any possible confrontation that could have happened before the shooting. 

According to the Post-Gazette, Liu received his doctorate at the University of Singapore in 2012 before coming to the U.S. to work as a postdoctoral fellow at Carnegie Mellon University. The 37-year-old started working at the Pitt School of Medicine about six years ago.

“He was just starting to obtain interesting results," Bahar said. "He was sharing with us, trying to understand the mechanism of infection, so we will hopefully continue what he was doing.”

Neighbors said Liu and his wife mostly kept to themselves. Bahar said the couple didn't have any children together and Liu was an only child.

“This is someone who we're going to miss very much at the department,” Bahar said.