Hello. I try to release objects associated with TCombobox like this

Hello. I try to release objects associated with TCombobox like this

procedure FreeObjectsInCombobox(ACombobox: TComboBox);
var i: Integer;
obj: TObject;
begin
for I := 0 to (ACombobox.Items.Count - 1) do
begin
obj := ACombobox.Items.Objects[i];
if Assigned(obj) then
begin
FreeAndNil(Obj);
ACombobox.Items.Objects[i] := nil;
end;
end;
end;

There are objects of different types in Combobox, but all of them inherited from TObject

But if object is already released condition "Assigned(obj)" still passing fine and there is access violation on "FreeAndNil(obj)"

Can anybody give me advice how to properly release objects or check if it is already released?