The shooting occurred about 11 a.m. Jan. 20 in the 600 block of South Humphreys Avenue, near Humphreys Avenue Elementary School. Sunday's vigil was held at the same location, where a makeshift memorial lined the sidewalk.
The owner of the car was struck in the hand and another friend in the backseat was unhurt, but relatives say Gutierrez was struck in the head. She was pronounced dead at the scene.
Gutierrez's loved ones remembered her as a loving person who lit up every room she was entered.
She was very closed to her siblings, parents and extended family, said Patricia Ramirez, Lexus' aunt.
Gutierrez "wouldn't let a day go by without saying hello to them, whether it was in person or if it was through a text message or phone call," Ramirez said as she stood near the memorial, comprised of balloons, posters, flowers and photos.
The Los Angeles County Sheriff's Homicide Bureau is investigating the shooting. The department said a small, four-door sedan was spotted leaving the scene.
22-year-old woman fatally shot near East LA elementary school, prompting search for gunman
"A car drove by and just shot at them and unfortunately she was the one that was hit," said Ramirez said last week. "She had a big heart, she was kind, she was very loving and she was loved."
Gutierrez's family is hoping the crime was recorded on nearby security cameras, or that someone will come forward and identify the shooter.
"All we're looking for is justice, justice for an innocent person," Ramirez said. "I can't understand, I can't comprehend how you can continue to go on with your life knowing that you took the life of someone innocent."
A GoFundMe page has been set up to help Gutierrez's family pay for funeral expenses.
Anyone with information that could help find the shooter is urged to call CrimeStoppers at (800) 222-TIPS (800-222-8477).