Breakdown of Soruşturduğum kadarıyla, bu sadece basit bir kaza değil.
bu
this
bir
a / an
değil
not
kadar
as ... as; until, up to
Questions & Answers about Soruşturduğum kadarıyla, bu sadece basit bir kaza değil.
How exactly does soruşturduğum kadarıyla break down to mean "as far as I investigated"?
It combines the verb soruşturmak (to investigate) with the participle suffix -dık (which becomes -duğ due to consonant mutation and vowel harmony) and the first-person possessive -um (my). Adding kadarıyla creates the structure meaning "to the extent of my investigating" or "as far as I investigated".
Why does kadar become kadarıyla in this grammar structure?
The word kadar (amount/extent) takes the third-person possessive suffix -ı to link back to the preceding action, followed by the buffer -y- and the instrumental suffix -la (with/by). Literally, the phrase means "with its extent." You will see this fixed kadarıyla form in almost all "as far as [subject] knows/sees" expressions.
Could I use araştırdığım kadarıyla instead of soruşturduğum kadarıyla here?
Yes, but it changes the nuance slightly. Soruşturmak specifically implies a formal inquiry, interrogation, or official police-style investigation. Araştırmak is used for general research or looking into a topic. Since this sentence is about discovering something isn't a "simple accident," the detective-like soruşturmak fits perfectly.
Just as a quick refresher, why is it basit bir kaza and not bir basit kaza?