A Sin to Steal from Thieves? Wondering...

[Jaypeeto4]

I was wondering about something.
I know that if you discover that someone stole your car, and you find your car in that person's yard, you have a right to get that car back, because he or she, that person,
took it without your permission.
That, of course, is clear cut.

But that got me wondering (and I have seen others ask this question on other forums too, rhetorically),
IS it a sin to steal from a person or persons, whom you know
is/are, stealing not only from you, but from many other people??
i.e., is it a sin to steal from a person or persons who are habitual thieves
((even if there are no human laws against their particular form of thieving, which GOD knows for sure **is** thieving, even if the nation or state has not addressed it)) ??

I know stealing is wrong, but like every other issue, there are many variables.
For example, there is "no salvation outside the Catholic Church"
That is 100% true. But we know, for sure, that there are many variables that must be
applied to that concrete statement, that absolutely true statement, and the Church itself teaches that, in fact. LUMEN GENTIUM teaches plainly that there are many people outside of the visible parameters of the Roman Catholic Church who can be, and many times are, in the state of saving grace and that, if they despite their ignorance of Catholic doctrinal facts, do follow their conscience AS IT is prompted by the Holy Spirit, they can indeed reach salvation. So, the concrete, 100% true statement that there is "no salvation outside the Catholic Church" nonetheless has many variables.

We have a bully at work, a very vicious bully, who has, through intimidation, stolen tens of thousands of dollars in commission that rightfully belongs to me and my co-workers, and they for some reason, won't fire her ((although I do know for a fact that she, this vicious and purely Evil woman, has threatened these managers that if she is terminated, she will drag every last one of them into court, my god she is totally evil and worse, tells people that she, this malicious, hateful, habitually thieving bully, is a Catholic, which embarasses me and the other Catholics at work to death )).
Would it be a sin for her victims to steal from her what she has stolen from them, since
they have no official, legal recourse against her? ((Bullying is not addressed in Federal Law with regard to workplace bullying, unless you can possibly make it fall under Harassment, which IS officially Illegal. Her form of stealing from her co-workers, also, is not officially addressed in the Law, either, so we have no Legal recourse, none, to get back the vast money she has stolen from us by bullying us out of our sales****)).

****this she is able to do because company policy forbids us to fight at all
in front of customers. So, after we have helped a customer (that she initially greeted, maybe five hours previously, but thereafter totally ignored) for an hour and are now ringing them up (for sales of sometimes thousands of dollars) she Always, WITHOUT FAIL, appears at the register, loudly demanding "her" sale and customer, stealing from us the fruits of our Labor, not her labor, for she did none, and we can't fight her in front of the customer, can't find a manager right away, so she rings it up under her number, gets our sometimes $100 or more of commission, the customer, perplexed, leaves, and it's our word against hers, we have no "proof" that she stole anything, which she definitely did. This woman again, is pure Evil. I have stopped praying for her. I had masses said for her, enrolled her in prayer leagues, everything, to obtain graces for her, and she just gets more and more evil every day, so I have given up on her. Someone else can pray for her. I've enrolled her in the prayer groups (and paid the enrollment fees), so let their prayers avail for her, if anyone's prayers even can, because I am sick of wasting my prayer time on this willful wicked woman. Sorry for that rambling, but I'm frustrated and sick and a nervous wreck and in this horrific economy can't afford to quit my job, nor can my co-workers, to get away from her.

I don't steal, but I'm wondering if it would be sinful for any of my co-workers to "recover" their losses to her by, say, taking her "even exchanges" under their number, which would cause her to lose the commission she earned ((or often DIDN'T **rightfully** earn)) from the item being even-exchanged when she rang it up.??

Thanks all!!
Jaypeeto4