The Gunners decided to move for Shkodran Mustafi after baulking at Bayer Levekusen's asking price for Toprak.
The Gunners sent a scout to watch the defender play in Roma's clash with Porto.
The Villa chairman says Gana is following ex-captain Fabian Delph in appearing to betray the club.
The 21-year-old midfielder knows what it takes to make it into the Forest first-team.
Could Hannover 96 striker Mame Biram Diouf be a good option for Arsene Wenger?
News, views and rumours relating to Manchester United in the past 24 hours.