The search for missing California teen Sierra LaMar continued on Thursday, when authorities investigating her disappearance conducted an underwater probe after sonar images detected a suspicious object in a reservoir earlier this week.

Fox News reported that divers from Santa Clara Sheriff's Office searched the Chesbro Reservoir after the images showed some areas of concern. Investigators will continue their underwater search on Friday and the Uvas Reservoir will also be explored.

LaMar, a 15-year-old sophomore at Sobrato High School, has been missing since March 16 when she was last seen leaving home on Morgan Hill. She was headed for the school bus stop at the time.

Investigators told Fox News that LaMar was likely a victim of an acquaintance abduction.

Based on the size and shape and shadowing that we're seeing from the side scan sonar, we'd just like to go back and take a second look at them, Santa Clara County sheriff's Lt. Dan Rodriguez said. They are larger than normal objects.

LaMar's personal effects that include a cell phone and bag were found after her disappearance. Her pants and shirt were also found folded.

LaMar is 5 feet, 2 inches tall and has brown hair. She lives with her mother and mother's boyfriend. Her biological father is said to be a registered sex offender but is not a suspect in this case, according to Fox News

The teen's family is offering a $10,000-reward for any information that leads to her safe return.