This is what I remember from the Garland hearing:
"When Tyndale subsequently ordered Garland be
held in custody for an additional 48 hours during which police can continue to interview him, Garland said a quick “thank you,” smiled into the camera and then exited the hearing room at the detention facility."
http://news.nationalpost.com/news/c...between-person-of-interest-and-missing-family
I understand that to mean that Garland could be detained for questioning for up to 48 hours. At the end of the 48 hours, he had to be either arrested or released. I think that the arrest of Kevin on Friday was timed to give police more than 48 hours, because his release, or arrest, has to be processed on a week day - Monday for Friday detentions. Any press release/conference would follow the processed arrest.