  Brown sent an unsigned letter of apology to Wall, which Wall said she received last week , she had asked for one after the incident occurred .
<coherence>   Brown sent an unsigned letter of apology to Wall, which Wall said she received last week , she had asked for one after the incident occurred .
 Wall had asked for an apology after the incident. Brown sent an unsigned letter of apology to Wall, which Wall said she received last week , she had asked for one after the incident occurred .