Arianna Fitts would be 11 years old today, and if she is still alive she may be living under another name with no memory of being called Arianna.The girl was never found after her mother, Nicole Fitts, was found murdered and buried in a shallow grave under some plywood in San Francisco's McLaren Park, in early April 2016. Fitts had been working at Best Buy and her daughter had been staying full-time with a babysitter, Helena Martin, and her husband, Devon Martin, for about a month in Oakland when she disappeared.Family members had not seen the girl in several months, and coworkers said Nicole Fitts had been going to meet with the Martins, with whom she was in some sort of conflict, before she went missing on April 1, 2016.No arrests were ever made, and Arianna Fitts remains a missing person. She would now be 11 years old.Arianna in 2016, left, and the FBI's latest age-progression image, right.As an earlier anniversary of Fitts's disappearance approached last year, SF-based FBI agent Katherine Zackel said, "We don't consider this to be a cold case... We're getting active leads, we're getting new information all the time.""The investigation into Arianna Fitts’s disappearance is still very active," said the FBI's San Francisco office, in a new statement to KRON4. "We are confident that there are individuals who have information about where she may be, and we encourage them to come forward and speak to law enforcement and help bring Arianna back home."Anyone with information about Arianna, or about a girl matching the progression image who is around 11 years old, is asked to call the FBI San Francisco Division at 415-553-7400 or go to tips.fbi.gov.