Complex sentence: While at Maidstone, Hanratty came to the attention of a researcher, a "participant observer" who lived and worked alongside the inmates; he was later to remark upon Hanratty's "gross social and emotional immaturity".
Split into simpler sentences: While at Maidstone, Hanratty came to the attention of a researcher, a "participant observer" who lived and worked alongside the inmates. He was later to remark upon Hanratty's "gross social and emotional immaturity".