Authorities are searching for a driver who led state troopers on a high-speed chase on the Downtown Connector Wednesday night before crashing into three other vehicles, killing an 18-year-old woman and a 3-month-old boy.

The driver of a BMW coupe ran from the wreckage after crashing into the vehicles on 10th Street, according to the Georgia State Patrol. A passenger in the back seat of a Nissan Altima, identified by authorities as Anjanae McClain of Peachtree Corners, died at the scene.

A 3-month-old boy riding in the Nissan’s back seat was taken to Grady Memorial Hospital with critical injuries before being transferred to Children’s Healthcare of Atlanta at Egleston, authorities said. He died of his injuries Thursday afternoon, GSP spokeswoman Lt. Col. Stephanie Stallings confirmed.

“I’m so sad that she’s gone,” McClain’s mother, Qiana Harlem, told Channel 2 Action News. “I don’t even know how I’m gonna go on like this.”

Three other passengers inside the Nissan were injured and taken to Wellstar Atlanta Medical Center, where they were stable Thursday, according to authorities. Three people in the two other damaged vehicles were not seriously hurt.

Stallings said a trooper first attempted to pull the BMW over on I-75 South near Howell Mill Road after spotting it and another vehicle traveling “at a high rate of speed.” The second vehicle sped off, but Stallings said the trooper caught up with the BMW and clocked it at speeds in excess of 120 mph.

The trooper turned on his blue lights to attempt a traffic stop on the BMW shortly after 9:30 p.m.

“The vehicle slowed momentarily then accelerated, initiating a pursuit,” Stallings said in a statement to Channel 2 Action News. “The trooper pursued the fleeing vehicle as it traveled, recklessly passing other vehicles and traveling through a construction zone at a high rate of speed.”

The chase continued south on the Downtown Connector before the BMW exited onto 17th Street onto an access road, she said. It crossed 14th Street and approached 10th Street, where the Nissan was stopped. After striking the Nissan on its left side, the BMW hit two other vehicles also stopped on 10th, according to authorities.

“The trooper approached the crash scene shortly after it occurred,” Stallings said. “The driver of the BMW, suspected to be the owner, immediately fled from the crash scene.”

Authorities have identified the driver as a 25-year-old man after he was seen on nearby security cameras. His name was not released, although Stallings said he will face several criminal charges related to the pursuit and crash.