It’s been a while since I’ve seen the movie. Did the Empire know the plans had been transmitted to Raddus’ ship before they boarded her? Or did they look through the logs, and figure it out after the Blockade Runner’s escape?
In hindsight, it might have been a good idea to not kill Take it! guy and find out what he was handing off. I presume the troops may have captured some other rebels alive for interrogation though.