The former Cornell student who faces federal weapon charges appeared in court Wednesday.
Charges stem from the 2015 death of his father.
A murder trial for Charlie Tan ended in a hung jury, and the judge dismissed the case.
Tan was re-arrested late last year on federal gun charges.
Prosecutors now have to convince a judge that certain statements allegedly made by Tan should be allowed into evidence at his upcoming trial.
The evidence includes incident reports, 911 dispatch transcripts and statements from two responding officers who spoke with Tan the night his father was killed.
Investigators say Tan persuaded a friend to buy the shotgun that was used to kill his father, after a Cortland County Walmart refused to sell him one
If convicted, Tan faces a maximum of 10-years on each count, plus possible fines.
The defense says they're moving forward as usual.
"To say that we are worried about it I don’t think is accurate,” said Tan’s Defense Attorney Brian Decarolis. “What our job is to do is to protect Charlie Tan's legal rights and if we feel there are legal rights that were in some way, shape or form impinged upon then we are going to challenge them."
No decision was made, and the hearing was adjourned for 2 weeks.Tan's trial is set to begin sometime in June.