It looks like they're hoping this case will just be forgotten about. The following from an NBC News station:

The Saginaw County Medical Examiner tells Mid-Michigan now it may be several months until a cause of death is determined due to toxicology results.

Mid-Michigan NOW asked the CDC when we know the exact cause of death of the 13-year-old and we received the following statement:

Normally when CDC meets with the Advisory Committee on Immunization Practices (the next schedule meeting will be posted here: https://www.cdc.gov/vaccines/acip/index.html it reports its findings, in a summary fashion, not by individual cases; CDC will also be publishing a paper in MMWR on myocarditis. I don’t have a target date for that paper yet.

This website is also updated with new information on several conditions that CDC is closely monitoring, like anaphylaxis, thrombosis with thrombocytopenia and myocarditis: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/adverse-events.html

Several months? How can that be?

I tried the links given. They don't work.