LOS ANGELES (KABC) -- The District Attorney's Office is reviewing an incident last year in Boyle Heights in which a sheriff's deputy's vehicle slammed into multiple pedestrians, killing two young children and critically injuring their mother.A witness who saw the horrific incident unfold told Eyewitness News she didn't hear a siren from the police SUV as it barreled through the red light of the intersection, slamming into another vehicle and triggering the chain reaction.According to investigators' reconstruction of the November 2017 incident: the sheriff's patrol vehicle was headed southbound on Indiana Street when it stopped at a red light at Whittier Boulevard. That is when the deputies responded to a call of an assault with a deadly weapon involving a gunshot victim.The deputy behind the wheel was still in training and her trainer was in the SUV with her.The SUV turned on the flashing lights, but not the siren.The patrol car then accelerated into the intersection against a red light and struck a Honda Accord heading east on Whittier. That car spun out of control and hit a Honda Odyssey stopped at the light.The sheriff's SUV swerved to the southeast, hit a pregnant pedestrian and then drove up on the sidewalk along Whittier. The SUV bounced off the side of a Wells Fargo bank, then struck the mother and her two children.It continued out of control, struck another pedestrian and a cement trash can and then one more pedestrian.The two boys were killed and seven others were injured.The witness who saw the crash told Eyewitness News that a Metro bus was blocking the view of the Honda Accord as it entered the intersection on the green light. The Honda driver couldn't see the flashing lights of the patrol vehicle and there were no sirens as an audible warning.That lack of a siren is a key element in the DA's investigation of a possible manslaughter or felony reckless driving case.Prosecutors are considering criminal charges against Carrie Robles-Placencia -- the deputy behind the wheel, who was going through training.Investigators determining that the deputy's light bar was only activated a second or two before the crash, but that the siren was never turned on.They also say the deputy's SUV was traveling at a high rate of speed.The witness told ABC7 the deputy gunned it from a stopped position.Robles-Placencia is still working as a deputy but in a non-driving role, according to the department.The father of the two dead boys is suing LA County and the sheriff's department. The lawsuit alleges the deputy didn't have the siren on, was driving in a careless, distracted and reckless manner, and didn't have adequate training.