Chris Cornell's family just got shut down by the City of Detroit, which refused to release information surrounding the singer's death, because the City claims it's still "an open investigation."

We've learned the family's lawyer, Kirk Pasich, sent a Freedom of Information request to the City asking for the police and toxicology reports. The City nixed the request, saying releasing the info would "compromise and/or interfere with their investigation."

The family says it's "mystified" the Medical Examiner announced to the world Chris' death was a suicide when the full autopsy hasn't been completed. 

Chris' wife, Vicky, says the family still has several unanswered questions about what led to her husband's death and she thinks the toxicology reports will answer those questions. The intimation ... maybe Chris was so high on drugs he was not in his right mind and did not consciously try and kill himself.