(CNN) -- The toddler whose body washed ashore in Texas last month has been tentatively identified as a 2-year-old girl, and her mother and a man identified as her boyfriend were arrested Saturday, the Galveston County Sheriff's office said Sunday.
Police believe two-year-old Riley Ann Sawyers may be "Baby Grace."
Investigators believe the child they dubbed "Baby Grace" is actually 2-year-old Riley Ann Sawyers, the Galveston County Sheriff's office said Sunday.
DNA analysis is still in progress to confirm that identification.
The child's mother, Kimberly Dawn Trenor, 19, and a man identified as Royce Clyde Zeigler II, 24, were arrested Saturday on charges of injuring a child and tampering with physical evidence, the sheriff's department said.
The couple lives in Spring, Texas, a Houston suburb about 75 miles north of Galveston.
Their bonds were set at $350,000 each.
The arrests followed searches conducted Saturday after a November 7 tip, the sheriff's department said.
Deputies and FBI agents plan to release more information at a news conference Monday, Galveston County Sheriff's Maj. Ray Tuttoilmondo said.
The girl's grandmother, Sheryl Sawyers, of Cleveland, Ohio, told CNN affiliate WKYC that Riley Ann has been missing since June. Watch Sawyers family describe their fears before child was identified »
On October 29, a fisherman discovered the body in a blue Sterilite plastic container on an uninhabited island in Galveston's West Bay.
Police dubbed the dead girl "Baby Grace," and asked the public for help in identifying her.
A medical examiner said the child's skull was fractured, and a forensic dentist estimated her age at 2 to 3 years.
In composite sketches, the girl is wearing a pink skirt and matching top -- clothing authorities said she was wearing when she was found. The other sketch, a close-up rendering of the child's face, shows a fair-skinned toddler with long blond hair.
"She is more to us than just a case number, more to us than just an unidentified body. She is very much a human being," Tutoilmondo said last month. "She is someone's child, someone's grandchild, someone's cousin, someone's best friend, and to us, that is the most important part about this case."
"We have adopted the name of Baby Grace because, there again, that is part of the emotional part of this case for us," he said, holding a tiny sneaker identical to one of those the child was wearing when she was found. E-mail to a friend
CNN's Hank Bishop contributed to this story.