its odd that they asked u to leave straight away..
if i had a business and someone wrongly accused me i simply provide them with proof why i didnt do it..
their behaviour suits someone that has heard those words before.
i think your only hope is making contacts.. find someone who knows a cop or works for a telephone company that can find out home addresses, phone numbers, bank details, criminal history, business history... whatever.
going to court with that evidence in my opinion will get you no where.
your better off paying your mate with insurance $1000 to install an alarm in his car and use it as bait.
you have a better chance than $3000+ fees and no evidence
goodluck