Justin Rowe and Cooper from Columbo goest to college also had quite good alibi, they were in a classroom while the murder happened, because everything was remotely controlled.
And Hasan Sallah...simple alibi (he was in his rooms), but nobody can prove he wasn't really there.
About Riley Greenleaf...I liked his alibi, but he traps himself fast, if I remember correctly, he mentions that there were 2 people that crashed to him, although Columbo doesn't tell that.So if he was dead drunk, how would he remember that there 2 and not remember anything else.And another thing-if he was really dead drunk, he wouldn't been able to drive a car and he should have at least partial memory, at least from my own experiences-if I was ever dead drunk, I still have some memories and wasn't able to operate any machinery.Maybe drunk Cassidy is exception.
I haven't seen this one in a good 8 or 9 months now...but I like the scene where Riley stubles into the party at the beginning of the episode and confronts his former writer, the writer who wants to move on to a new publisher.
The scene were Columbo is at the restaurant and orders Chili is funny too.