yes, evidence can always be subpoenaed.

Why does the DEA do the same undercover drug buy over and over?

Police many times use the same informant, because they believe they are reliable.

Low level bac readings while on probation

Any amount of alcohol detected could result in you being put in jail.

I have a friend who a jury found guilty. Can they appeal their sentence if they enter a plea after the jury verdict?

It depends on whether or not a appeal waiver was signed

Do I keep waiting...or is there no case?

More likely than not they are waiting on blood tests results

It depends on the plea bargain

I had 3 Dwi's and serve 16 month of a 3 year sentences in state prison in 2004..I Tried to purchase a firearm was denied.WHY.

If you have a felony conviction within 5 years you cannot purchase a fire arm.