what are possible outcomes of a 2nd degree murder case with no physical evidence and with witnesses who refuse to comply with prosecution?

When first arrested there were witness statements. There has been no physical evidence , no weapon, no dna , or anything. The states only evidence are witnesses that they have not been able to get in contact with and who are refusing to comply. there were intial statements taken at the scene but no pre trial hearing for defense to cross examine. What are possible outcomes?