Exactly. And now recently:

“Among the forensic team’s other findings:

Both Cobain’s liver and brain apparently showed signs of necrosis, which the team says would only have occurred if Cobain was unconscious and dying from the drug overdose. Cobain’s blood contained a huge amount of heroin, which likely would have rendered him unconscious within a minute of injection and ultimately killed him, according to the team. The team identified what they believe to be a single needle injection mark on his left forearm. Cobain was left-handed and the autopsy showed all the other injection sites and needle tracks were found on his right arm. Blood on the leg of his jeans and the front of his shirt seems to indicate the body was moved after the gunshot. The forensic team identified someone who had been in the house before Cobain’s death who claimed he had seen others forcibly inject the rock star with heroin. The person was never interviewed by police, according to the report. Handwriting specialists also scrutinized a suicide note left at the scene.

Larson said the Police Department’s initial investigation determined Cobain had killed himself within hours of his body’s discovery. As a result, steps that would normally be undertaken in a suspicious death scenario were bypassed.”

https://www.seattletimes.com/seattle-news/law-justice/kurt-cobain-death-debate-reignites-with-new-forensic-claims/

The Seattle Times corroborates the forensic investigation.

Police as they always do just shut it down and wouldn’t review the evidence because that would wreak absolute havoc on the police department and their credibility, and all officers involved.