[verb (dictionary form)] + 始末だ [verb ない-form] + 始末だ [sentence] + という始末だ この / その / あの + 始末だ
始末だ says that things have gone from bad to worse and ended up somewhere deplorable: "and now he's even…", "it's come to this". It follows a dictionary-form verb, or the ない-form, at the end of a story about something going wrong, and the speaker is criticising, not just reporting.
The verb stays in the dictionary form even when the events are past. Words that mark the last step – あげく挙句, とうとう, ついには, しまいには – often lead up to it, and まで ("even") is common in the last clause.
始末だ always looks back in exasperation. A good result, or one you are neutral about, takes ことになった or けっか結果 instead.
始末だ belongs to writing and to formal or exasperated speech. In everyday conversation, a plain past with とうとう or まで says the same with less weight.