The Good Boy - S4-E3
Continuity mistake: When Cal Ritter's wife comes to his furniture studio to talk with him, the clock shows the time as 4:45. After they talk for two minutes, the security guard enters and says, "It's 5:00 and my ride's here. I just want to let you know I'm leaving."
Answer: I did not see this episode, but YES. Both prosecution and defense lawyers use investigators to search for and uncover evidence that is legally admissible.