Fascinating question... There's this standard case for law students (here in Germany): A man wishes his wife was dead. He sends her out to the mailbox on rainy

Fascinating question... There's this standard case for law students (here in Germany): A man wishes his wife was dead. He sends her out to the mailbox on rainy day, muttering "I hope you get hit by lightning" under his breath. She does get hit by lightning and dies. Murder?