( CNN ) -- Police have ratcheted up charges against the girlfriend of an Alabama father , days after searchers found fragmented remains they say are of the second of the man 's young children , tossed along the side of a remote highway . Mobile , Alabama , police spokesman Christopher Levy said Monday that Heather Keaton would be charged with two counts of aggravated child abuse and two counts of abuse of a corpse -- one count each for the deaths of Jonathan DeBlase , 3 , and his sister Natalie , 4 . The children 's father , John Joseph DeBlase , 27 , was arrested December 3 and is now charged with two counts of murder and two counts of abuse of a corpse . John DeBlase 's lawyer , Jim Sears , said Monday that his client maintains `` his innocence in regards to the death of the children . '' Sears added that DeBlase might consider pleading not guilty by reason of disease or mental defect ( equivalent to an insanity plea in other jurisdictions ) . The investigation kicked off November 18 , when Keaton told Louisville , Kentucky , police that she needed protection from DeBlase , who she claimed was holding her against her will . She was arrested in early December and charged , at the time , with two counts of willful abuse and neglect of a child . Around 1 a.m. Monday , Keaton arrived from Kentucky to face the four additional charges , according Levy . By early in the afternoon , she had not been questioned by Mobile police . Her arrest followed the discovery Saturday morning of remains that authorities believe are those of young Natalie DeBlase . Searchers had planned to canvas woods abutting a six-mile stretch of highway just northwest of Citronelle , Alabama , about 50 miles north of Mobile , based on information provided by John DeBlase . But they found the remains -- less than half of a young body , including a skull and miscellaneous bones -- around 9 a.m. , within 30 minutes of starting the search . `` We did n't cover hardly any of it , because we found her so quickly , '' said Levy . `` She was where he said she would be . '' Levy said the girl was not buried , but had been laid `` in the woods , not far from the roadway , '' just as DeBlase had told authorities . The Alabama Department of Forensic Sciences is examining the remains to confirm that they belonged to Natalie . The girl was last seen in March , when authorities believe she was killed . Jonathan DeBlase had not been seen since June , police said . Investigators believe he was slain around that time . Remains that police believe are those of the young boy were found last Wednesday near Vancleave , Mississippi . The cause of death for both sets of remains has not yet been determined , police said . DeBlase and Keaton blame each other for the siblings ' deaths , authorities said . Police , who did not know the children were missing until November 19 , contend that DeBlase allowed Keaton to abuse the children by restraining them with tape , putting socks in their mouths and confining them . A day earlier , Keaton signed a domestic violence petition in Louisville that said , `` I feel he may have murdered his children , because he said they were non-responsive . He would not let me check on them . '' She said DeBlase had told her `` choices were made ... and he had to do what he had to do . '' According to a police complaint , DeBlase between March 1 and November 19 allowed Keaton to tape Natalie 's hands and feet , put a sock in her mouth and place her in a suitcase that was put in a closet for 14 hours . He also allowed Keaton to tape Jonathan 's hands to the side of his legs , tape a broom handle to his back , place a sock in his mouth and then make the child stand in a corner all night when the couple went to bed , according to the complaint . DeBlase and Keaton have one infant daughter together , according to Keaton 's account in the Kentucky police report . Police said one reason Keaton claimed she needed protection from DeBlase was that she feared for the safety of the infant , who was with her in Kentucky . HLN 's Natisha Lance contributed to this report .
NEW : Keaton maintains his innocence in his children 's deaths , his lawyer says . Heather John DeBlase is being charged Monday with less than half counts of abuse of a corpse . Louisville police say they believe the remains of both children have been found . The case opened in Monday , though the children had n't been seen for months .