Probably at least as effective and a lot shorter:
"I'd love to go out with you, but that would violate the terms of my parole. But if you can wait a year, my sentence for poisoning my wife will be finished and you can come round for dinner."
Some mobile phones can be made to ring as if someone is calling, providing a convenient excuse to leave a meeting or get away from someone. Pretend to answer, then say something like "No, the drugs are supposed to arrive
tomorrow" or "Good, tell the snipers to stand by and move the first team into place. I'm looking at the suspect now".
(Disclaimer: I have never actually tried any of these, so I don't know for sure how effective they will be or what to tell the police later.
)
