Netflix’s Narcos is set to begin season 4 with a brand new cast, and the streaming service has announced that The Flash and Legends of Tomorrow actor Matt Letscher has joined the series in a new series regular role. The actor is the third to have been cast since it was announced the true-crime drama would undergo something of a shift after three seasons following the dismantling of Pablo Escobar’s empire and the Cali Cartel, alongside Agents Javier Peña (Pedro Pascal) and Steve Murphy (Boyd Holbrook), with the former taking over as series lead in the recently concluded third season. Those changes include a shift in location from Colombia to Mexico, and the addition of Diego Luna and Michael Peña in as yet undisclosed roles.

The shift in setting and main characters also comes with a change in the series’ time period. Rather than move forward from where the series left of in season 3 — the mid-‘90s — Narcos will be taking a trip in the way back machine, moving things to the late ‘70s and early ‘80s to explore how the Guadalajara cartel came to be and how it managed to fall into business with the Colombian drug trade. That presents a number of new possibilities for the series and it seems showrunner Eric Newman is taking advantage of that by bringing Letscher on to play a DEA agent.

As reported by Deadline , Letscher will join season 4 to play James Kuykendal, a member of another team of DEA agents investigating the Cali Cartel. The news of Letscher’s casting also mentioned that Kuykendal’s team will be utilizing information obtained by a mole the DEA has placed in the organization. Though it’s not official yet, it stands to reason that either Luna or Peña might be playing Kuykendal’s mole.

For his part, Letscher is probably due to play a character operating on the right side of the law. For the last few years, he’s been running around The CW’s Arrowverse as Eobard Thawne/Reverse-Flash, generally making life miserable for Barry Allen before heading off to Legends of Tomorrow to form the Legion of Doom with Malcolm Merlyn and Damien Darhk. But Letscher’s resume also includes a four-episode stint on Boardwalk Empire season 5 as Joseph P. Kennedy, a role in Spike Jonze’s Her, and a role on The CW’s The Carrie Diaries.

So far, there are no details on how many episodes of Narcos season 4 Letscher will actually appear in, but considering the role is a series regular, chances are good Agent Kuykendal will be around for most of the season. Filming is already underway on the new episodes, with the plan for the new season to hit the service sometime later this year