Paraffin test is unreliable

Dear PAO,

My brother was shot by Mark. Luckily, he survived the attack. The only pieces of evidence we have against Mark are the CCTV footage from the crime scene and the paraffin test conducted by the police. The investigator informed me that the paraffin test yielded a negative result, and he seemed concerned when relaying this information, which makes me worry that it may clear Mark of any responsibility. My suspicion even grew when I heard Mark bragging about his innocence, claiming that the paraffin test result would prove it. Is the paraffin test vital in proving the guilt of Mark? Will the negative paraffin test lead to the dismissal of the criminal case?