CHICAGO — Police hope witnesses or surveillance video can lead them to the an arrest of the person responsible for killing three people, and critically injured another outside a bar in Portage Park.

Monday afternoon, police said they are questioning a person of interest. No further information was provided.

The Cook County Medical Examiner’s Office identified the three victims as 50-year-old Ricky Vera, 26-year-old Mario Pozuelos and 24-year-old Mercedes Tavares.

Police said around 2:30 a.m. Sunday near North Central Avenue and West School Street, a man fired shots at a group of people outside Vera Lounge, and then fled the scene in a dark-colored SUV, according to information from the Chicago Police Department.

During a press conference Sunday morning, Cmdr. Joseph Brennan said there was an argument inside the lounge before it spilled into the street.

On top of the three people who died, a 25-year-old woman was taken to a local hospital in critical condition with a gunshot wound to the head, police said. The woman underwent a 12-hour surgery and is fighting for her life.

Relatives say the woman is victim Ricky Vera’s daughter. Family members tell WGN the father and daughter are related to the owner of the lounge.

No one is in custody and the incident is still under investigation by Area 5 detectives.

While detectives are still in the early stages of their investigation, Brennan said they believe only one suspect was involved.

If you or someone you know has information that could help detectives make a breakthrough in this case, anonymous tips can be placed online at cpdtip.com.