Why did the police arrest me for buying drugs instead of the dealer?

Unless the dealer simply managed to escape, probably one of two things happened. Either, 1) the seller happened to be an informant for one of the arresting officers, and she prefers the dealer stay out of prison so that he can continue being useful to her as an informant, or 2) the seller was actually an agent of the police. If the second of these two situations is true, then the drug buyer may have a way to avoid a conviction on this case.

Confidential Informants

Everyone accused of a crime has the right to subpoena all witnesses to the crime to call in his defense. If the seller was an agent of the police, that means the police asked him to sell drugs, and they of course will want to protect his identity. This by itself is fine, as there's nothing wrong with police using confidential informants...It is done all the time, in fact. However, a "confidential" police agent who witnesses a crime loses his right to confidentiality - the right to subpoena a witness in your own defense is a constitutional right! 

A qualified and experienced drug charges lawyer will want to bring a motion to discover who the seller was. If a judge agrees that they have to disclose his identity so the buyer's lawyer can interview and subpoena him, the police may prefer to dismiss the charges rather than lose their informant. Since this defense is based upon U.S. Constitutional protections, this strategy applies in all states. Still, the degree to which the courts honor this motion to discover the police agent may vary.

Getting Help from a Drug Charges Lawyer

If you were just arrested and have yet to retain an attorney, do so immediately, or use the Free Case Evaluation link to submit your case to an attorney right here.