Staff members will return to work on Friday at the Florida school where a gunman shot and killed 17 people in the deadliest shooting ever at a U.S. high school, district officials said, with students expected back next week.Marjory Stoneman Douglas High School in Parkland near Fort Lauderdale also will hold a voluntary orientation for students and parents on Sunday and hopes to have students resume classes the following Tuesday on a modified schedule, Broward County Public Schools said in a statement.Nikolas Cruz, 19, a former student accused of the shooting, made an appearance on Monday in Fort Lauderdale court where he faced 17 counts of premeditated murder.