Who writes an editorial in The Maycomb Tribune comparing Tom Robinson's death to "the senseless slaughter of songbirds"?

In chapter 25, Scout reads Mr. B. B. Underwood's editorial in The Maycomb Tribune regarding Tom Robinson's unfortunate death. After being wrongly convicted of assaulting and raping Mayella Ewell, Tom Robinson was taken to Enfield Prison Farm, where he attempted to escape and was shot seventeen times by the prison guards. Scout mentions that Mr. Underwood did not write about miscarriages of justice and simply believed that it was a sin to kill cripples. Scout mentions,

He [Mr. Underwood] likened Tom’s death to the senseless slaughter of songbirds by hunters and children. (Lee, 244)

Mr. Underwood's editorial comparing Tom's death to the senseless slaughter of songbirds alludes to Atticus's comment in chapter 10 when he tells his children that it is considered a sin to kill a mockingbird. In Mr. Underwood's editorial, Tom is a metaphorical songbird or mockingbird. Tom is considered a symbolic mockingbird because he is innocent, defenseless, and harmless. Mr. Underwood's comments regarding Tom's senseless death underscore Atticus's lesson about protecting innocent beings. Similar to a mockingbird, which spreads join and is a vulnerable being, Tom Robinson is a benevolent person and does not deserve to die such a brutal death. After reading Mr. Underwood's editorial, Scout fully understands the metaphorical meaning of Atticus's earlier comment and grasps the situation by saying,

Atticus had used every tool available to free men to save Tom Robinson, but in the secret courts of men’s hearts Atticus had no case. Tom was a dead man the minute Mayella Ewell opened her mouth and screamed. (Lee, 245)

Later on, Scout metaphorically applies Atticus's lesson regarding the importance of protecting innocent beings by comparing Boo Radley to a mockingbird.