INDEPENDENCE, MO. ? For the third time this year, police are investigating the suspicious death of a toddler in this Kansas City suburb. The two earlier deaths led to murder charges.

The latest death came at 6:30 p.m. Wednesday, when 21-month-old Breanna M. Leonard died three hours after paramedics brought her to Medical Center of Independence.

An autopsy conducted Thursday found Breanna died from a lacerated liver caused by blunt-force trauma, said Bill Pross, an Independence Police spokesman. There was also considerable bruising on the toddler’s body, consistent with physical abuse, he said.

The death was ruled a homicide, Pross said. Evidence in the case was to be presented to the Jackson County Prosecutor’s Office, with charges expected as early as this morning.

Authorities have not released the name of Breanna’s 21-year-old mother nor her 18-year-old live-in boyfriend. Both remained in police custody Thursday.

Police said the boyfriend called the mother around 3 p.m. Wednesday and said the child was having trouble breathing. The mother came home from work immediately and called 911.

Paramedics found Breanna with a shallow, rapid breath and a weak pulse.

In April, Tammy Yates, 22, and her live-in boyfriend, Bobby L. Matthews, 29, pleaded innocent to second-degree murder charges in the death of 23-month-old Alexis Smothers. Police said the girl had been beaten and shaken.

Earlier this month, authorities indicted Lena M. Buhr, 27, and her boyfriend, Byron Griffin, with second-degree murder, along with various other charges, in the death of 3-year-old Anthony Buhr.

Both had earlier pleaded innocent to similar charges.

The indictment said Anthony Buhr was shaken and strangled early on June 6, causing fatal injuries. Investigators said Buhr helped her boyfriend clean up blood splattered against her bathroom wall and did not call for help until she no longer could feel a pulse.