Walker complained that he felt threatened by others in neighborhood . Someone videotaped brutal attack that killed him Thursday . The 16-year-old was more polite than other kids , activist said . Four have been charged with murder ; suspects ' ages are Four , 18 , 17 and 18 .
Derrion Albert complained that he felt threatened by others in neighborhood . Someone videotaped brutal attack that killed him Thursday . The 16-year-old was more polite than other kids , activist said . Four have been charged with murder ; suspects ' ages are 16 , 17 , 18 and 19 .