Rich was shot several times near his home in the Bloomingdale neighborhood, where there were no witnesses to the shooting. The Omaha, Nebraska, native was conscious and breathing at the scene, but officials said that he died a short time later at a local hospital.
He wanted to "make a difference, do good things, treat people fairly, and try to make the world better," his father remembered.
"He was a caring person and he wanted to make a difference. Unfortunately those visions, those ideas are going to have to be unfulfilled," his father said.
Rich was talking on his cell phone with his girlfriend when she heard noise on his end of the line, his family said. There was some noise, but Rich had told his girlfriend not to be concerned and the call ended.
"We may never know what actually happened," said his mother, Mary Rich.
She added that her son often told her to always "laugh" and "make the most of every moment because you never know when the next moment isn’t going to exist."
DNC Chairwoman Debbie Wasserman Schultz issued a statement on Monday mourning the loss of Rich.
"He saw the great potential of our nation and believed that, together, we can make the world a better place. He was a joy to have as a member of our team, and his talents, intelligence and enthusiasm will be deeply missed by the many friends, colleagues and co-workers who worked by his side in service to the highest ideals of our democracy," Wasserman Schultz said. "We send our deepest heartfelt sympathies to Seth’s family, and we will keep them in our thoughts and prayers as we try to pick up the pieces and carry on the work that was so important to Seth and to us."