Could someone please explain the use of か and よう in the second sentence below from an article about the recent terrorist attack in Turkey?
My best translation (please correct if it is not accurate):
The Turkish police consider the use of the bomb an act of terrorism. They explained that an approximately 12 - 14 year old child detonated the bomb (made the bomb explode) he was holding by himself or someone (else) detonated the bomb by remote control.
My main concern is the use of か pointed out in bold. Could someone please elaborate on this usage. I was under the impression that か cannot be used to link two independent clauses but I am evidently wrong. I translated it as "or" due to the context but it was basically a guess.
I'm also interested in why よう was used in the と clause and how the meaning changes if it is omitted (させたと説明 rather than させたようだと説明).
Finally, less importantly, what is the subject of 使った in this sentence from above 爆弾を使ったテロだ? I'm fairly certain my translation is accurate in meaning but the use of a relative clause in the Japanese confuses me. I would have expected this to be expressed with こと like 爆弾を使うことがテロだ or maybe some noun that expresses a specific incident rather than a general concept.