The taxi driver's wife actually knew his husband is a murder all along, but that's 10 years before the corpses were found and the family is big and happy, so she chose not to say it. Spica tried to reveal it, the wife tried to stop it, but couldn't. The news got up, spica bought a thank-you gift, bla bla bla, the girl came back from the hospital and asked "is it true that the teacher suicide?"