If the said employee suddenly left the organization (without tendering resignation or any information about his leaving) with any of your official and confidential data, you must send him a notice on his address and if have proof of his act and have proper documentation of giving loan amount, need to file an FIR and also must take legal help in this regard.
But I dont understand how you feel like to "complaint or inform other companies about his mischief" is the right and easiest way to take action against him, which is actually not gonna work for you until you take any firm legal action.
This is in addition to what Mr Anil Arora has written. As per your post, the employee in question has committed three misconducts. One is failure to repay the loan taken from the company, second is theft of confidential data and third one is abandonment of employment.
For the former two, do you have adequate evidence? How did you disburse the loan? Do you have standard form? If yes, have you taken signature of the two guarantors?
As far as theft of confidential data is concerned, did you assign him responsibility for the safe custody of the data? Do you have proof of assigning this responsibility? Do you have adequate proof of theft?
I recommend you ordering domestic enquiry and investigate the each misconduct. On the strength of the enquiry report, you may lodge police complaint for the theft of data and failure to repay the loan.
Rather than conducting official enquiry, what you wish to do is to issue circular in your industry to notify misconduct of this employee. What you will achieve by doing this? Your assumption is that on getting this information, other companies will not hire him and you will be able to block his future employment.
In case if you do not have adequate evidence of the theft of confidential data and disbursement of loan then what if the employee in question files defamation suit against your company?
Your query of issuing circular to other companies is childlike behaviour. If some truant classmate plays horseplay, we tell other classmates and try to bring psychological pressure on him. We cannot be crying baby while running "Corporate company". We must handle the matter professionally.
Final comments: - Your post leaves evidence of your poor business writing skills. There is great scope for improvement on this count. This is my secondary observation. If you do not improve your business writing skills then lack of these skills may hold your future growth.
All the best!
Anil Arora & Dinesh Divekar have already touched-upon the aspects of 'what you need to do'.
However, I would like to point-out to one other aspect--looks like your [or your Company's] focus is MORE to teaching this guy a lesson THAN protecting your Company's interest.
Let's presume there's a way to 'screw-up' [forgive me for using this phrase--but that's what your intent seems to be] this ex-employee's career/life. This is NOT to say that this person is blemishless--with the limited inputs given by you, frankly, it's tough to give a clear verdict.
Now WILL THIS ENSURE your Company's confidential info that you say he stole comes back AND is not already into the wrong hands by now? Surely NOT.
Pl get your focus/priorities right in the first place.
Not sure of your designation--but IF it's @ the lower/middle level, suggest advise your bosses to go for a Police Complaint [meaning Criminal Complaint].
Obviously you need to ensure you have the Documentation to back whatever you allege to the Police about this guy--else this step would be counter-productive for you & your Company.
This is more than likely to show-up during any Background Checks about this person by ANY Company [MNC or otherwise]--NOTWITHSTANDING what happened in the recent Uber case.
You can also use to highlight his case in the NASSCOM Skills Directory--pl use the 'research' facility @ the top of this page--you will find earlier threads related to this aspect/topic, from where you can pick-off.
All the Best.
As suggested by all, build up a case with documentary evidences. Once you have the evidences, consult a lawyer whether this will attract penal action and after his ratification file a FIR . He will then face the consequences accordingly. Never ever think of making attempts of ruining someone's career without evidences, since, that will boomerang very badly on you, in case he takes legal action against you and your company. And am sure your company is in the business of making money and not ruining careers. Mudslinging is something Corporates must never resort to since they have a credibility to protect.