The syntactic complexities of English sentence structures induced the Indonesian students’ sentence-level accuracies blurred. Reciprocally, the meanings conveyed are left hanging. The readers are increasingly at sixes and sevens. The Sentence Crimes were, therefore, the major essences of diagnosing the students’ sentence-level inaccuracies in this study. This study aimed at diagnosing the 2nd-year PNP ED students’ SCs as the writers of English Paragraph Writing at the Writing II course. Qualitatively, both observation and documentation were the instruments of collecting the data while the 1984 Miles & Huberman’s Model and the 1973 Corder’s Clinical Elicitation were employed to analyse the data as regards the SCs produced by the students. The findings designated that the major sources of the students’ SCs were the subordinating/dependent clauses (noun, adverb, and relative clauses), that-clauses, participle phrases, infinitive phrases, lonely verb phrases, an afterthought, appositive fragments, fused sentences, and comma splices. As a result, the SCs/fragments flopped to communicate complete thoughts because they were grammatically incorrect; lacked a subject, a verb; the independent clauses ran together without properly using punctuation marks, conjunctions or transitions; and two or more independent clauses were purely joined by commas but failed to consider using conjunctions. In conclusion, the success of the Indonesian and or other EFL students constructs sentences rests upon the knowledge, sensitivity and the mastery of complex syntactic structures through transformational/structural grammar.