His testimony doesn’t appear to be very reliable. At least according to this New York Times reporter
That should have been the end of it. Guede initially told one story: that he had sex with Kercher and then went into the bathroom, plugged in his iPod, and came out to find a strange man standing over her with a knife.
Then, months later, Guede changed his story: he said that strange man was now Sollecito, assisted by Amanda Knox in a sex game that went wrong. Neither of them had been named by him before. Guede denied being the killer.
His testimony doesn’t appear to be very reliable. At least according to this New York Times reporter