Aggravated assault

The statute of limitation (2 years) has run, so you probably don't have a case no matter what the state of the evidence. Typically, the state of the evidence is also poor at this remove. However, sometimes there is documentary evidence like video tapes and / or police and hospital reports. It's very unlikely you can pursue this at such remove. At this point, you're probably best off letting it go.

In PA, the Statute of limitations for aggravated assault is 5 years, unless the victim was an officer that was on duty, and then there is no statute of limitations that applies.

The statute of limitations for aggravated assault is generally 5 years, so there is no time bar to bringing a prosecution for the offense after 3 1/2 years. However, the second question is nearly impossible to answer without more information. If the evidence is very strong and not time sensitive (e.g.- strong medical evidence and video documentation of the incident) then the passage of time may not prevent filing. If the evidence is more tenuous (e.g.- just based on the testimony of the alleged victim) then the passage of time may have eviscerated the case. One thing remains constant: if you think you may be charged with aggravated assault, you should be asking this question in a private consultation with a criminal defense attorney. Only an attorney with knowledge of your case can really advise you on how to proceed.