Police have arrested a family member in connection with the death of a 3-year-old Bronx boy.

According to authorities, Fernando Yensi, the step-grandfather of Poseidon Quinones, has been charged with manslaughter, but declared his innocence after being taken into custody. The 33-year-old has a criminal history with two prior sealed arrests.

The medical examiner ruled Quinones' death a homicide caused by blunt force trauma to the abdomen. He was found unconscious at his grandmother's home over the weekend, with bruises all over his body.

During a brief court appearance Friday night, prosecutors say Yensi acknowledged that he was the only adult present when Poseidon suffered fatal injuries.

Quinones had been living with his grandma, 46-year-old Madeline Yensi, who is the suspect's wife. She was given legal custody of the boy, despite protests from his biological mother, Ashley Ramirez, who is blaming child services.

Ramirez says she feared for her son's safety and begged child services not to place him with his grandmother and step-grandfather.

There is no word yet on the circumstances that led to Quinones' death. News 12 reached out to his grandma, but she declined to comment.

Yensi is being held without bail and is due back in court on Nov. 26.