Why is there no official announcement from GRE as yet ?
Quite possibly because they're not ready to make a public announcement. What started these threads wasn't due to any official announcement, but from private information from one (or more) of the affected individuals that the company that they worked for had shut down operations and they no longer had a job.
Quite often any official public announcement of this type has to be crafted carefully and only released after specific legal and contractual steps have been taken. A hasty or poorly worded announcement or officially releasing it without completing those necessary steps can open the company officers to legal action, both by regulating agencies and creditors. That's why we often have information of the kind we have gotten here leaked by non-official sources well prior to any official announcement.
There's also the possibility that the company isn't ready to make any official announcement since they could be working to spin off, sell, or otherwise save what part(s) of the company that they can. Any official announcement may cause those negotiations to end without any hope of keeping any part of the business alive.