1)
Did Ba'alei Shechem kill Gid'on's sons?
1.
Malbim (4): Through giving money to Avimelech, they participated in the murder.
2)
Who are "Ba'alei Shechem"?
1.
Radak: They are the masters of the city and its leaders. They are the primary people of the city.
2.
Radak citing Targum Yonasan: They are the residents of Shechem.
3)
Why did he say "Ki Achichem Hu'?
1.
Malbim: This was your intent, and not to return the good that Gid'on did for you.