If it's stolen from a person, then it will be, for instance, "украдено у Льва Петровича", if we are talking here about about a company or organization, "украдено из" would be correct (or, to sound less strict, would be with a higher probability more appropriate), like in "украдено из Петровского парка" or "Украдено из ООО "Амурские авиасистемы". The neuter form would be ok for gender-agnostic designation, one can say "украдена у Льва Петровича" however this would be very unnatural without the actual noun: "[эта] книга украдена у Льва Петровича".
However! While those phrases are technically correct nobody in Russia talks like that and use this particular form in sake of purposes you've mentioned. It'll be just "собственность Льва Петровича" / "cобственность Петровского парка" etc.