The death of a 2-year-old Minneapolis boy, who police say was physically abused by his mother, has been ruled a homicide.

An autopsy determined the boy, Ona'Je Prince Sincere Jackson, died May 4 of "complications of multiple blunt force injuries," according to a report released Saturday by the Hennepin County Medical Examiner's Office. No other details were released.

Authorities said they found evidence that the boy and his younger brother were physically abused by their mother. Navonna L. West, 25, was charged on May 6 with two counts of malicious punishment of a child in connection with injuries suffered by her 4-month-old son. The charges also implicated West in the death of her 2-year-old.

According to the criminal complaint and police: Officers were called to the home in the 2400 block of S. Oakland Avenue late in the afternoon of May 4. They arrived to find West performing CPR on Ona'Je. He died at 6:18 p.m. that evening at Hennepin Healthcare in Minneapolis, the medical examiner's report said.

The officers saw fresh bruises and scratches on the 2-year-old. An autopsy detected "blunt force injuries in various stages of healing," the charges read.

A hospital examination of the 4-month-old revealed bruising on his torso, genital injuries, chemical burns near his navel, possible burns on his back, blood in his right eye, scarring on his nose and pigmentation loss on each side of his head.

The baby also had suffered broken ribs and had fluid in his abdomen. A test disclosed that he had been exposed to fentanyl, a powerful synthetic opioid that has killed tens of thousands of Americans.

Questioned after her arrest, West "attempted to deny or minimize the injuries to her children," according to the charges. After being told of Ona'Je's death, West "claimed the injuries were from them being sick," the charges said.

West was released from custody on June 1 after posting a $50,000 bond. A spokesman for the Minneapolis Police Department said they had no updates on the case.

Staff writer Paul Walsh contributed to this report.