SARASOTA COUNTY — John Lee clearly recounted the days leading up to the murders of Traci Nabergall and Jason Salter while on the stand Thursday, painting his relationship with Nabergall as that of protector; Nabergall, he said, was addicted to prescription pills and Lee said he made a promise to her family to make sure she was safe.

But as he tried to recall the details of Jan. 24, 2011, the night of the murders, his testimony became less clear, and instead he remembered only small things, flashes of sudden violence. He recalled storming into Salter’s house and seeing Salter, 46, standing over Nabergall, 39, repeatedly stabbing her with a knife; and then taking the knife from Salter and stabbing him in order to protect himself. Other details remained elusive, he testified.