One suspect has been taken into custody in the case, but his family says police have the wrong man. Austin is charged with murder and armed robbery.
The funeral mass for the 23-year veteran was held at Saint Francis Assisi Roman Catholic Church.
Before losing consciousness, Officer Soto called 911 and described the offender's vehicle. He died the next day. Romberg died at the scene.
"It's as trying as it is for family, often times tragedy like this will give strength and serve us as a reminder of our commitment to serve," said Supt. Jody Weis, Chicago Police Department
Police arrested Austin after they say surveillance video and witnesses placed him and his car at the scene. Austin's attorney and family say his car was in the shop on Wednesday and that police have the wrong person.
Romberg was buried over the weekend. Officer Soto was buried after the mass.
"He's going to be dearly, dearly missed. This was a very tragic event in our family. We're familiar with these tragic events and it's just very sad no matter how often it happens," said Lydia Arnold, Officer Soto's cousin.
"He was gentle. He cares for everybody and he was a wonderful person," said Fernando Romero, Officer Soto's uncle.
One of Soto's brothers in law delivered the eulogy. He spoke of Soto's sense of humor and infectious smile. Officer Soto was buried at the Queen Of Heaven Cemetery.