ROCHESTER, N.Y. -- An unassuming apartment building at 193-195 Leighton Avenue in Rochester shows fews signs of its tragic history. Police made a grim discovery there on January 10, 2016. It's been two years since police began to investigate the quadruple homicide. To date, no one has been arrested.

The victims, who were all from Rochester, included 28-year-old Michael Royal, 29-year-old Jennifer Leasure, 45-year-old Michael Adams and 22-year-old Lachelle Powell.

Royal and Leasure were said to be engaged and Jennifer was one month pregnant.  Their families did not respond to our requests to talk to them for this story.

For investigators, the worst part of this case is not being able to offer closure.

"It's terrible for the families," said investigator John Brennan, with the Rochester Police Department. “One particular father calls monthly. It kills me not to be able to give him good information, or to say that we have a good lead and we are following something up."

Meanwhile, the Bureau for Alcohol, Firearms, Tobacco and Explosives is offering a $15,000 reward for any information leading to the arrest and prosecution for the crime. So far, investigators say no one credible has come forward.

"We are just hoping that someday, somebody who has the direct knowledge has the courage to come forward will tell us the story of who did it,” Brennan added, “the key to this investigation is that we need someone who has direct knowledge."

Police are asking for anyone with information to call Crimestoppers or 911.