Meanwhile, authorities said charges against two men already in custody could be upgraded to a hate crime. Menelik Jackson, 24, and Jovan Battle, 32, have each been charged with first-degree murder.
WATCH: Supt. Johnson discusses charges in shooting of Officer Rivera
Police said Jackson fired into a car Saturday in River North, killing the 23-year-old officer and critically wounding another man. Police said Battle was a co-conspirator.
Officers used Rivera's handcuffs when taking Jackson into custody.
RELATED: 2 charged in fatal shooting of Officer John Rivera
The two men suspected of killing Rivera may have shot him simply for being Hispanic. This occurred after police said the men were involved in an unrelated dispute at the former Rock N' Roll McDonald's, which police say involved a group of Hispanic men traveling on board a party bus. Now, police say hate crime charges may be filed.
"He was searching around for the party bus, the party bus had left the area, so I guess he settled for the first Hispanic he saw," Chicago Police Superintendent Eddie Johnson said.
RELATED: Off-duty Chicago cop killed in River North shooting identified
That night Rivera had been out with friends, including his girlfriend. She survived the shooting after the officer's final act of bravery, shielding her and others from gun fire.
FUNERAL ARRANGEMENTS FOR OFFICER RIVERA
Visitation will be held 3 p.m. to 9 p.m. Thursday at Elmwood Chapel, 11200 S. Ewing Ave., Chicago.
Funeral prayers will be at 9:15 a.m. Friday at Elmwood Chapel. Funeral Mass starts at 10 a.m. at the Church of the Annunciata, located at 11128 S. Avenue G, Chicago.
For more information visit Elmwood Funeral Chapel and Crematory.