my car was vandalized, and now it wont crank. been told it was ECM but not 100%. on 2005 Cadillac STS

i was able to drive it home but it took me about 4 hours to get it cranked and taken to a body shop and from there it hasnt cranked and it isnt throwing any codes. i need help on finding a problem.

Asked by for the 2005 Cadillac STS