Los Angeles ? Nineteen inmates were injured Wednesday in a series of racially motivated brawls at a county jail where deadly rioting occurred last weekend, authorities said.

Four different fights involving more than 450 black and Hispanic inmates occurred at the Pitchess Detention Center in Castaic, about 40 miles northwest of downtown Los Angeles, sheriff’s officials said.

Four inmates were transported to hospitals. Fifteen more were treated at the facility for minor injuries. No sheriff’s deputies were hurt.

All seven of the county’s jails were placed on lockdown after the fights.

Another section of the same detention center was hit with rioting Saturday between Hispanic and black inmates that killed one man and injured more than 100 others. It was followed by two other melees Monday night that caused one minor injury.