The phrase "and when they conclude" is correct and usable in written English.
It can be used to indicate a point in time when a group or individuals finish a task or discussion.
Example: "The committee will review the proposals, and when they conclude, they will announce the selected candidates."
Alternatives: "and once they finish" or "and after they wrap up".
Afghan officials investigated the events in the Nerkh district, and when they concluded that the accusations of misconduct by the team were true, the head of the Afghan military, Gen. Sher Mohammad Karimi, personally asked the American commander at the time, Gen. John R. Allen, to hand Mr. Kandahari over to the Afghan authorities.
My own perspective is informed by Meisenhelder and Marcum when they conclude, "People who were more stressed used more coping mechanisms, most commonly looking to God for strength, prayer, displaying a flag, seeking time with friends and family, and contributing money to help the victims".
As a second step, Western governments should insist on more stringent social and environmental conditions for mining rare earths and other raw materials when they conclude the partnership accords with countries like Kazakhstan.
But candidates sometimes flip-flop when they conclude that the alternative might be more costly.
Some people always drop out during recessions, when they conclude that prospects of finding work are slim.
Eurosceptics are still wrong when they conclude from all of this that the entire European project must be trashed.
Yesterday's terrorists can indeed become tomorrow's peacemakers, but only when they conclude that there is no other option.
While placing blame on both sides, the US report apparently accepts that American and Afghan commandos were wrong when they concluded there were no Pakistani troops in the area where they were conducting an operation.
So I suggested that on this one, the factoid that stuck in my craw was that Mateen had been interviewed twice, and after the second time when they concluded he was not an imminent threat because they couldn't get a strong enough connection between him and the terrorist group he was boasting about, they said, "Okay, we've got to close this case". And when they closed the case his name came off.
