He soon enrolled in the recently constructed Purdue University where he was a member of the Sigma Pi fraternity and Acacia fraternity. While at Purdue, Leslie was captain of both the school's football and baseball teams and became one of the school's "immortal" players. As one of the school's star players, his team was on course to win the state championship in 1903. On October 31 he and his teammates took a train from Lafayette to Indianapolis to a match against Indiana University. As the train neared the 18th Street crossing in Indianapolis, it collided with another train, and Leslie's coach was shattered. One member of the team miraculously landed on his feet and was unharmed after being thrown out a window. The other eighteen boys, including Leslie, were pronounced dead at the scene and taken to the morgue.