George suspects Mr. Roland, but cannot immediately convince the others. The children later discover the "secret way" (which was in Quentin's laboratory after all) which leads to the two artists' room in Kirrin Farm and George uncovers the stolen papers by mistake and they try to escape through the secret way, but the thieves almost outrun them but retreat when George threatens to set Timmy loose on them. The five also discover that Mr. Roland was behind them and imprison Mr. Roland and the two artists behind a room until the police arrive and arrest them.
George suspects Mr. Roland but cannot immediately convince others. The children later find the "secret path" (which was in Quentin's lab) leading to the artists' room at Kirrin Farm, and George accidentally discovers stolen papers. They attempt to escape through the secret way, but the thieves nearly catch up until George threatens to release Timmy, who causes them to retreat. The five also learn that Mr. Roland orchestrated it and imprison him and the two artists in a room before the police arrive.