Demolition work has begun along a short stretch of Linn Street for old buildings on the Saint Mary`s property in Marshalltown just south of the downtown area. As a result, Linn Street between First Street and Center Street is closed between now and Saturday at Noon. Among the structures to go are the former convent which was the victim of arson a couple of years ago. The former school and gym will also come down. The work will continue well into the month of September.