In a press conference Wednesday morning, authorities identified the child as Jayden Alexander Lopez from Houston.
Police say they arrested Jayden's mother, Rebecca Suzanne Rivera, and her girlfriend Dania Amezquita Gomez, who also both live in Houston.
It's believed both women were present at the time of Jayden's death.
RAW VIDEO: Officers announce arrests in case of Jayden Lopez
Rivera has been charged with felony tampering with or fabricating physical evidence because she allegedly dumped his body. She is being held on $250,000.
Gomez has been charged with a misdemeanor because police say she knew about the crime and was also present when Jayden's body was dumped on the beach. She is being held on a $100,000 bond.
Mom, Rebecca Rivera, CHARGED with dumping “Little Jacob” whose name is now confirmed: JAYDEN LOPEZ, 4. Mom’s girlfriend charged with misdemeanor, meaning she KNEW Rivera dumped Jayden. #abc13 #breaking pic.twitter.com/68TfTOvZJd— Courtney Fischer (@CourtneyABC13) June 20, 2018
Authorities say Rivera was arrested on Tuesday. Gomez was arrested earlier in the week.
They have not been able to find the boy's father.
Investigators also revealed Wednesday morning that there was a 3-year-old child in Rivera's household. He has been removed from the home.
TIMELINE: How police worked to solve the case of "Little Jacob"
According to police, Jayden showed signs of being malnourished. He also had bruises on his body prior to his death.
Officials say they received leads, which led to the suspects' names. Someone also recognized Jayden from a photo.
"This case has been immensely difficult to work for our Special Agents who are parents. While our job is to investigate these types of crimes, it is especially difficult when the victim is a defenseless child," said #FBI Supervisory Special Resident Agent Bryan Gaines pic.twitter.com/PAyBqaxdNO— FBI Houston (@FBIHouston) June 20, 2018
Authorities have been working on the case since Oct. 20, 2017, when Jayden's body was found.
Until he was identified, he went by the name "Little Jacob." A sketch was released to draw help from the public along with a crime scene photo earlier this year.
FULL VIDEO: Galveston police announce charges and arrests in "Little Jacob" case
An exact cause of death has not yet been released.
The investigation is ongoing.
Wow. This is a perfect example of how “Little Jacob” has affected people in #Galveston. As soon as Lisa heard Jacob identified to be Jayden Lopez, she came here to pray. #abc13 WATCH ➡️➡️➡️ pic.twitter.com/OdZ7HUcTIg— Courtney Fischer (@CourtneyABC13) June 20, 2018
WHAT WE KNOW ABOUT THE LITTLE JACOB CASE