This thread is getting off topic, perhaps we could start another thread on the knife combatives for law inforcement.
To answer the original question the biggest difference beteeen the tonfa and the police baton is the 90 degree handle.
To see a good clip of use check out Mel Gibson in "leathal weapon", plus a triangle choke to boot.
Although leathal weapon its only a movie I beleive the usage of the baton was very realistic the "triangle" was text book gracie juijutsu .
And if your one of those where "reality is the only game in town" tm check out the Rodney King
beating/arrest.
Regards