-LRB- CNN -RRB- -- Before dying , 2-year-old Riley Ann Sawyers was beaten with belts , picked up by her hair , thrown across the room and held under water , according to an affidavit from the Galveston County Sheriff 's Office . Police believe 2-year-old Riley Ann Sawyers is `` Baby Grace . '' The affidavit says the girl 's mother , Kimberly Dawn Trenor , described to police how her daughter died and was put in a plastic storage box that Trenor and her husband , Royce Zeigler , later dumped into a Galveston waterway . Trenor told police Zeigler tried to commit suicide the weekend before Thanksgiving , and wrote a note that said , `` My wife is innocent of the sins that I committed . '' The body of the then-unidentified toddler was found on October 29 . A fisherman found Riley 's body stuffed inside a blue storage container that washed up on an uninhabited island in Galveston 's West Bay . A medical examiner said the child 's skull was fractured , and a forensic dentist estimated her age at 2 to 3 years . Police dubbed the child `` Baby Grace . '' A police artist 's sketch of her was widely circulated in the news media and prompted a call to Galveston police from Riley 's grandmother in Ohio , who had not seen the girl in months . On Saturday , police arrested Trenor and Zeigler on charges of injuring a child and tampering with physical evidence , the sheriff 's department said . Their bonds were set at $ 350,000 each . The affidavit , obtained by CNN , says when police interviewed Trenor on November 23 , she `` gave a voluntary statement on video with her attorney present in which she describes her involvement , with Royce Zeigler , in the physical abuse , death and disposal of the remains of her daughter , Riley Ann Sawyers . '' Trenor 's statement said on July 24 , she and Zeigler both beat the child with leather belts and held her head under water in the bathtub . She said Zeigler picked the girl up by her hair and also threw her across the room , slamming her head into the tile floor . After her daughter died , Trenor 's statement said , she and Zeigler went to a Wal-Mart that night and bought the Sterilite container , a shovel , concrete mix , and other supplies . The statement said the box containing the child 's body was hidden in a storage shed for `` one to two months . '' Then , Trenor said , she and Zeigler carried it to the Galveston Causeway and tossed it in , and she saw it drifting away . Riley Ann 's father , Robert Sawyers , on Monday tearfully remembered her as a `` fun-loving girl ... with a big imagination . '' Watch Riley Ann 's father describe the little girl '' Riley was `` very active , very hyper , but also very well-behaved , '' Sawyers told reporters in Mentor , Ohio . She would play `` with a water hose ... spraying the whole patio soaking wet until she was done with it , '' he said , as he sat behind two photographs of his daughter , a toddler with wispy blond curls . Robert Sawyers ' mother , Sheryl Sawyers , said the family was `` devastated '' to learn that police believe Riley is dead . `` It 's hard to think that I 'll never see her again , '' she said , clutching a red Elmo doll she had planned to give Riley for Christmas . Maj. Ray Tuttoilmondo of the Galveston County Sheriff 's Department said Monday that authorities are `` fairly confident '' that the toddler whose body was found on October 29 is Riley Ann Sawyers . DNA analysis is still in progress to confirm the identification . The results will be available in two to three weeks , Tuttoilmondo said . Tuttoilmondo said Riley is originally from Mentor , Ohio , a Cleveland suburb , and that `` she and her mother came down to Texas earlier this year . '' The toddler was last seen in Texas `` three or four months ago , '' Tuttoilmondo said , although he did not know by whom . Tuttoilmondo said police did investigate whether Child Protective Services had taken Riley away , something the mother had reportedly alleged . Of that report , Tuttoilmondo said , `` What we believe is that is not what happened . '' The affidavit said Trenor admitted that after the body was found , Zeigler had her type up a fake letter from the Ohio Department of Children 's Services saying that Riley was to be taken away . Trenor left Ohio in late May , after filing an allegation of domestic violence against Robert Sawyers and reaching a joint voluntary agreement that gave her custody of Riley and gave Robert Sawyers visitation rights , the Sawyers ' family lawyer said Monday . `` She disappeared , '' Laura DePledge said Monday at the Ohio news conference with the Sawyers . Sheryl Sawyers said Monday that she saw widely distributed police sketches of `` Baby Grace '' and contacted Galveston police in November . The girl in the police sketches strongly resembles photos of Riley . `` No , I never did think it would end up like this , '' Sheryl Sawyers said Monday , eyes welling . `` I guess knowing is better than not knowing . '' The girl 's family in Ohio has been `` very helpful '' in this case , Tuttoilmondo said , adding that the FBI and a Galveston County police officer visited the family in Ohio on Sunday . DePledge said Riley was the product of a `` teenage pregnancy . '' Trenor and Robert Sawyers were together for two years as a result of the pregnancy , DePledge said , during which time they lived with Sheryl Sawyers . DePledge said Monday that the family , whose grief she described as `` simply overwhelming , '' wants Riley 's body returned to Ohio for a memorial service . `` What Riley needs is to be brought home , '' she said . `` I think this family needs some closure . '' Tuttoilmondo asked anyone who knew the child or her family to help detectives reconstruct the events of Riley 's short life . The toddler 's case has touched even hardened police officers , he said . `` Any way you look at it , we carry a piece of her with us , and we 'll always carry a little piece of her with us , '' he said Monday . He held up a small , pink-and-white shoe identical to those the child was wearing when she was found . `` That says it all . A little-bitty shoe . '' E-mail to a friend CNN 's Sean Callebs contributed to this report .