Human Rights watch, in my view, a
semi credible institution. They have been caught, on numerous occasions, inflating figures to prove a point (RE: refugees, murders, civilian casualties). That being said, anecdotal evidence such as these specific reports are probably verifiable.
Here, for example, is an article reviewing some of the allegations of execution of homosexuals. It cannot be denied, however, that the Iranian
government pursues anti-homosexual policies, just as the Bush administration does.