( CNN ) -- Forensic evidence found on property belonging to a missing California teenager led authorities to a man suspected of kidnapping and killing her , authorities said Tuesday . Sierra LaMar , 15 , of Morgan Hill has been missing since March 16 , when she left her mother 's home to walk to her school bus stop . Monday night , police arrested Antolin Garcia-Torres , 21 , also of Morgan Hill . He faces charges of murder and kidnapping in LaMar 's disappearance . Santa Clara County Sheriff Laurie Smith told reporters Tuesday that investigators believe LaMar is dead , although they have not located her body . `` We continue to pray until she 's found , '' LaMar 's mother , Marlene , said Tuesday . `` Our search still is not going to end . '' She implored Garcia-Torres to `` come forward and say where she is . '' Smith said Garcia-Torres has not been forthcoming with authorities . `` We have gained some value from our interviews with him , but nothing substantive , '' she said . LaMar 's purse and phone were found at different locations on the side of the road within two miles of the house . The purse had clothes neatly folded inside . Forensic evidence was found `` in multiple places '' on LaMar 's possessions , Smith said . She would not divulge the nature of the evidence . Physical evidence also links LaMar to Garcia-Torres ' vehicle , which was seized on April 7 . Garcia-Torres was identified March 28 after forensic evidence was run through a law enforcement database , Smith said . Garcia-Torres was in the database because he had a prior felony arrest for an assault , although the case was not prosecuted , she said . Since then , authorities have had him until 24-hour surveillance , she said . `` We were hoping that he would lead us to where Sierra was . '' The motive for the abduction is not known , she said , but `` it 's my belief this was purely random . It was an absolute stranger abduction . '' LaMar was `` a very social girl '' who was constantly in touch with her friends by telephone and through social media , she said . Since she was reported missing , she has contacted no one . In addition , some property found was items `` she would have taken with her , including medication , '' the sheriff said . Investigators believe Garcia-Torres acted alone , she said . `` These are very , very difficult cases , to prosecute a homicide when you have not found the victim , but it has been done and I think we have adequate facts , strong facts '' to show the teen is dead , Smith said . Authorities have not recovered a weapon and do n't know how long LaMar might have been kept alive or how she died , she said . Forensic evidence has also linked Garcia-Torres to one of three unsolved assaults in Morgan Hill in March 2009 , Smith said . In one assault , a stun gun was used on a victim who managed to escape ; another victim had her own knife used against her ; and in a third , a man tried to get into a woman 's car but was unsuccessful when she locked it . Smith said she could not remember which of those three Garcia-Torres was linked to . In April , Marlene LaMar , described her daughter as a focused student who was a cheerleader . `` She was passionate , '' Marlene LaMar told HLN 's Nancy Grace . `` She did dance , competitive dancing . And she also enjoyed cheerleading . She was driven . You know , she set the bar kind of high for herself as far as , you know , trying her best . '' Morgan Hill is about 22 miles southeast of San Jose . `` We still need your support , '' the girl 's father , Steve LaMar , told reporters Tuesday . `` We need to bring Sierra home . ... We want justice served . That 's what we 're looking for . '' CNN 's Greg Morrison contributed to this report .
NEW : This means the product will ship as received by the manufacturer, sealed, with all advertised components, and with the manufacturer warranty. NEW : Police are still searching for Sierra LaMar 's body . NEW : The suspect is also linked to a 2009 unsolved assault . The suspect faces murder and kidnapping charges .