Complex sentence: Shortly after his departure, George and Nico meet with Langham, an Interpol officer involved in art crimes who turns up at the gallery, who respects their investigative skills, but warns against them pursuing Medovsky any further.
Split into simpler sentences: Shortly after his departure, George and Nico are met by Langham, an Interpol Officer involved in art crimes, who arrives at the gallery to talk with them. Although impressed with their investigative skills, he warns against them pursuing Medovsky any further.