2 Maryland teens found shot dead the night before high school graduation

— -- Police in suburban Maryland are investigating the double murder of two teenagers who were set to graduate high school Tuesday, but were found shot dead Monday night.

After Montgomery County police officers responded Monday night to a report of the sounds of shots being fired, they found the teens inside a car parked on a residential street in Montgomery Village, about 23 miles north of Washington, D.C., Montgomery County police said.

The victims, identified as Shadi Adi Najjar, 17, and Artem Ziberov, 18, both sustained gunshot wounds and died at the scene, police said.

They were set to graduate from Northwest High School in Germantown today.

"For those of you who knew Artem and Shadi, we ask that you remember and celebrate them," Northwest High School Principal Jimmy D’Andrea said in a statement ahead of the ceremony. "They were both excellent students who had a positive impact on those around them, and they will be greatly missed."

A moment of silence was held at this afternoon's graduation.

At the ceremony, D'Andrea told the crowd that Najjar, who took higher-level courses including upper-level calculus, "was a natural learner who had a genuine interest in knowing and understanding."

"Any assignment completed was well done," D'Andrea said, "and he enjoyed learning most when he felt challenged."

He was also "incredibly kind and personable" and "always leaned over to help a classmate when they were struggling," D'Andrea said.

Ziberov, who planned to attend the University of Maryland, had a "dry sense of humor" "paired with a truly kind spirit," D'Andrea said.

He was a member of the National Honor Society and had earned over 260 hours of community service, D'Andrea said.

Ziberov was tri-lingual and was working on learning Japanese as a fourth language, D'Andrea said. He wanted to pursue a career in international relations, D'Andrea said.

The principal said he would deliver the teenagers' diplomas to their parents later this week.

Meanwhile, authorities "worked through the night" investigating the teens' murders, the police said. Crime Solvers of Montgomery County is offering a reward of up to $10,000 for any information that leads to an arrest.

Anyone with information is asked to call the police at 240-773-5070.

This isn't the first time a high school senior was killed close to their graduation date this spring.

In May in Irving, Texas, 18-year-old Ledajrick Cox was shot dead hours after his graduation.

And in May in Baton Rouge, Louisiana, 18-year-old Bryant Lee was shot dead days before his graduation.

ABC News' Sarah Shales and Dee Carden contributed to this report.