Were the Jewish believers Paul persecuted still Jews under the Law?
Yes, the Jewish believers Paul persecuted were still Jews under the Law. Paul recounts in his own experience that he persecuted those Jewish believers, yet they remained Jews under the Law. This is the point the context emphasizes, showing their continuing Jewish legal identity at that time.
Les teaches from Acts 9 that Paul recounts in his own experience how he persecuted those Jewish believers, but they were still Jews under the Law. He stresses that this is what he wants readers to see. The context adds that when chapter 10 is reached, Peter is still a law keeper, though that is for another time. This occurs around the big turning point in Acts, where God sends Saul as a chosen vessel to the Gentiles, kings, and the children of Israel.