( CNN ) -- Relatives of slain California 8-year-old Sandra Cantu expressed `` shock '' Saturday at news that a neighbor -- a Sunday school teacher whose daughter was a playmate of Sandra 's -- was arrested in the girl 's death . Melissa Huckaby was charged with kidnapping and murder in the death of 8-year-old Sandra Cantu . `` Just utter shock and disbelief , '' Sandra 's aunt Angie Chavez told CNN affiliate KOVR . `` I ca n't imagine a mother doing this to a child . '' Melissa Huckaby , 28 , was booked into the San Joaquin County Jail early Saturday and faces charges of kidnapping and murder in the death of Sandra in Tracy , California . Sandra was last seen March 27 in the Tracy mobile home park where she lived with her family -- the same mobile home park where Huckaby lives . The girl 's body was found Monday , stuffed into a suitcase submerged in a pond at a dairy farm . `` We have to live the rest of our lives without Sandra . [ Huckaby ] is in jail . She can still see her little girl grow up , '' Sandra 's uncle , Joe Chavez , told KOVR . He said the family is `` shell-shocked '' and hopes that in time they can learn to trust people again . `` Who can you trust at this point ? '' he said . `` Who do you know ? '' A police spokesman told reporters Saturday he `` could n't begin to theorize '' a motive for Sandra 's death . Watch police discuss the arrest » . Huckaby is the granddaughter of Clifford Lane Lawless , pastor at the Clover Road Baptist Church , which was searched as part of the investigation , Tracy police Sgt . Tony Sheneman told reporters . Huckaby taught Sunday school at the church , he said . In addition , Huckaby 's 5-year-old daughter was close friends with Sandra , who often played at Huckaby 's home . Earlier Saturday , Sheneman said he did not believe Huckaby had retained an attorney . In a Friday interview with the Tracy Press newspaper , Huckaby acknowledged owning the black rolling suitcase that held Sandra 's body , but said she reported it missing the day before the girl 's body was found . She said it disappeared the same day the girl was last seen . `` There 's been a lot of speculation on the news about what happened to my suitcase , '' she told the newspaper . `` It 's not my granddad 's . It 's mine , and someone took it . '' Police said Huckaby lives in the same mobile home complex where Sandra lived with her family ; the Tracy Press reported Huckaby lives with her grandparents . Police noted `` inconsistencies '' between comments Huckaby made to the newspaper and a previous statement she gave authorities , Sheneman said . It was one reason police asked her Friday to come to the station to be interviewed again . She drove there about 6 p.m. Friday , he said . Authorities believe Huckaby lied about the suitcase being missing , Sheneman said . Asked whether authorities believe Sandra 's death was planned , Sheneman said the question is `` not something I can answer right now '' but `` we do have an indication . '' He said authorities have found where they believe the girl was killed , but would not divulge that location to reporters . `` I could n't begin to theorize what her motive is , '' Sheneman said of Huckaby . During the Friday night interview with police , Huckaby was `` very relaxed for a bit , and then she became very emotional , and then she became relaxed again '' before appearing resigned , Sheneman said . He declined to say whether Huckaby had confessed , but said `` she revealed enough information that we had probable cause to arrest her . '' Huckaby was booked into the San Joaquin County Jail about 3:25 a.m. ( 6:25 a.m . ET ) , according to the county sheriff 's Web site . She is set to appear in court Tuesday . Police took Huckaby into custody about 11:15 p.m. Friday ( 2:15 a.m . ET Saturday ) , Sheneman said , but she chose to continue talking with them for more than two hours . Authorities told Sandra 's family of the arrest about 2:15 a.m. local time , he said . `` They were in disbelief . '' Watch neighbors remember slain girl » . Police have had contact with Huckaby before , but she does not have a record of violence , Sheneman said , but did not elaborate . He said no other arrests are expected in Sandra 's death . Citing court records , the Tracy Press reported Huckaby pleaded no contest January 9 to a felony charge of second-degree commercial burglary and a misdemeanor charge of property theft with a prior theft , burglary or robbery . A criminal complaint says she was jailed in Los Angeles County on a property theft conviction in 2006 and that she attempted to steal from a store in November 2008 . According to the complaint , she is on probation in San Joaquin County and is due back in court April 17 . Asked about the court records , Huckaby told the newspaper it was n't her and that she did not know why the address and cell phone number in the court documents match her own . `` I do n't know what to say , '' she said . `` That 's not me . '' Police believe that by the time Sandra was reported missing , she was already dead , Tracy Police Chief Janet Thiessen told reporters Saturday . `` There was some speculation early on that [ the suspect ] would be a man , '' Sheneman said Saturday . `` It 's unusual for a woman -- statistically , according to the FBI -- to be involved in anything like this . '' The day Sandra was last reported seen , she returned home from school , kissed her mother and left to play with a friend who lives nearby . A short time later , wearing a pink Hello Kitty T-shirt and black leggings , she left to go to another friend 's home , according to a family spokeswoman . Police said the girl 's clothing helped them identify her body . Huckaby told the Tracy Press that Sandra stopped by her home that day to ask if she could play with Huckaby 's daughter , but Huckaby refused because she wanted her daughter to pick up her toys . Sandra left for another friend 's home , Huckaby told the newspaper . How Sandra died has not been made public . An autopsy was conducted earlier in the week , but CNN affiliate KRON-TV said results are not expected for weeks . Thiessen said Saturday any autopsy information as well as search warrants filed in the case remain under seal .
NEW : `` I ca n't imagine a mother doing this to a child , '' Sandra aunt says . NEW : Suspect 's daughter was Melissa Huckaby 's friend , playmate . Sandra was arrested on charges of kidnapping and murder , police say . Body of Sandra , Monday , was found 8 stuffed in a suitcase submerged in a pond .