[he closes his eyes briefly and inhales - his eyes open with a renewed focus. If he can deal with 1412, then a dead Shinichi will not phase him.]

Yes, case closed. I wasn't present myself, but it was discovered that a police officer was jealous of Kudo Yuusaku - blaming Yuusaku-san for stealing credit that he should have gained. He took revenge in the easiest way avaliable to him, since Yuusaku-san was out the country.

Your father was the main impetus behind the quick solving of the murder.