Eduardo Medrano Jr. is seen in an undated photo.

Alicia Torres is seen in an undated photo.

LANCASTER, Calif. (KABC) -- An 11-year-old girl was killed in a hit-and-run crash in Lancaster, and now the search is on for the driver responsible for her death.Shortly past midnight on Tuesday, two cars crashed at 20th Street East and Lancaster Boulevard. An 11-year-old girl, who was a passenger in one of the vehicles, was seriously injured and airlifted to an area hospital in critical condition.The girl, identified as Emily Tobar Echeverria on a GoFundMe page , died Thursday morning.The driver of the other vehicle, 25-year-old Eduardo Medrano Jr., was positively identified by multiple witnesses and was seen fleeing from the scene. He was picked up by another driver, Los Angeles County Sheriff's Department officials said.Detectives believe Medrano caused the crash by blowing through a red light in a Volkswagen.A search warrant was served Wednesday at Medrano's home, but he was not found. Investigators believe he is somewhere in the Lancaster area."His mother and his girlfriend or fiancee was there, and they pretty much told us that they knew nothing about it," said LASD Detective Gilberto Borruel.Borruel said investigators are looking for Medrano's girlfriend or fiancee, Alicia Torres, as a person of interest."The investigation is right now leading us to believe that Alicia Torres, his girlfriend or fiancee, is with him right now," Borruel said.Authorities believe alcohol was involved. A witness told Borruel that he was driving in the area and gave Medrano a ride without knowledge of the crash."He smelled alcohol in his breath. He was stumbling and staggering, and he did make some vulgar statements to him to reflect that he had been drinking," Borruel said.Authorities said the preliminary investigation suggests Emily Tobar was not wearing a seat belt and was ejected from the vehicle, described to be a Scion.The GoFundMe account was set up by loved ones to help the girl's mother."She is a single mother with multiple children, and right now she just needs all the help she can get, and obviously all the support and prayers for the family," Borruel said.If you would like to donate, visit www.gofundme.com/emily-tobar-echeverria . Emily Tobar's family says she will be an organ donor.Medrano is described as approximately 5 feet 10 inches tall, weighing 145 pounds with black hair and green eyes.If you have any relevant information about this case, you're urged to contact Sgt. Jennings with the Los Angeles County Sheriff's Department at (661) 940-3814 or Detective Borruel at (661) 940-3813, referencing File # 917-13826-1135-251.You can also submit anonymous tips by calling Crime Stoppers at (800) 222-TIPS.