In the light of recent developments, we have addressed the myth that HIV cannot be detected post-mortem on our Debunking denialist myths [1] page.
HIV can be detected post-mortem with a high degree of accuracy. This is very important because deceased tissue donors need to be tested to ensure that tissue recipients are not infected with HIV. See:
Links:
[1] https://www.aidstruth.org/denialism/myths
[2] http://www.ncbi.nlm.nih.gov/pubmed/16308764