Members of Boy Scout Troop 211 and their leaders thought their enclosed trailer was safe on church grounds.
The troop used the 6-by-9-foot trailer to store camping gear and many other items the scouts use for their adventures and learning experiences.
The trailer was stored at St. Alphonsus Catholic Church on Jackson Avenue near Calhoun Street. The scouts hold their weekly meetings at the church.
The trailer could have been gone a week before the scouts realized it was missing, Police Sgt. Terry Hines said.
The crime is grand larceny because the loss involves more than $1,000, Hines said.
"To them, what they lost is irreplaceable," he said.
Police have given a description of the 2014-model trailer and its contents to Coast law enforcement agencies, he said.