Suspects detained in investigation into fatal shooting of CPD Officer Areanah Preston

Note: An earlier version of this story on May 8 named five people who had been charged with robbery as part of an investigation into Officer Preston's death. 

CBS 2 corrected the story after three of those people were released without charges. The other two mentioned in the May 8 story were charged on May 10 with Preston's murder and a series of robberies.  Two others not mentioned in our May 8 report were also charged.

CHICAGO (CBS) --  Chicago Police have detained several people as investigators try to determine what led to the fatal shooting of CPD officer Areanah Preston, a police source said. 

A police source told CBS 2 that charges of armed robbery and possession of a stolen motor vehicle have been filed against some of the suspects. One more man has been identified as a suspect and remains at large. 

As investigators build the case, a source says those detained are connected somehow to Officer Preston's killing.

Other law enforcement sources, however, say no charges have been filed in the case. 

Chicago Police generally have 48 hours to charge someone with a crime after they've been taken into custody. But CBS 2 Legal analyst Irv Miller said there are some special exceptions.

"If the police don't think that the investigation is complete, and they want more time in excess of the 48 hours, they could contact what's known as duty judge," Miller said. "That's an on-call judge that is there to review documentation that the Police Department will submit to that judge to determine if there is probable cause that this person committed to crime - and therefore could be held more than 48 hours."

Miller said the period before potential charges are filed can be the most crucial — and time-consuming.

"Typically, it's DNA. They're trying to match up DNA - and that does take some time," Miller said. "There's also the issue of possible ballistics testing that has to be done, but that could be the relatively quickly."

Miller also explained that there is no such thing as a statute of limitations on a murder charge.

Preston, 24, was shot around 1:42 a.m. on Saturday in the 8100 block of South Blackstone Avenue in the Avalon Park neighborhood.

An arriving officer rendered aid, placed her into the back of a squad car, and took her to the University of Chicago Medical Center. 

After the desperate attempt to save her life, a police source tells CBS 2 she died from multiple gunshot wounds above the breast. 

Neighbors told CBS 2's Asal Rezaei they are still shocked. They say police cars have not left their street since the shooting in the nearly 48 hours since Preston was shot in front of her Avalon Park home.

It happened as Preston was getting home from her shift in the Calumet (5th) District.

Her neighbor and family friend Diane Ward heard the gunshots that would end up taking Preston's life. 

"Loud gunshots," she said. "I didn't think too much of it, so I went to bed and then woke up again because I heard a lot of traffic on the block, sirens and blue lights." 

Ward is still shocked that it happened in her neighborhood, an area she says hardly ever sees any violent crime. 

"This is the first time anything big has happened," she said. 

Ward said her Ring camera did not catch anything, but police confiscated surveillance video from both her neighbor's cameras. 

In the hours and days since the shooting, Chicago Police have been looking aggressively for those who were involved.

On Sunday night, an unsuspecting Uber driver found himself giving a ride to two of the suspects.

Chicago Police surveillance teams were following one of the suspects and arrested him moments after he got into the back seat of the Uber with another woman.

Pictures taken by the Uber driver show that a gun was recovered. Police reports say it was a semi-automatic 9mm pistol.

It is unclear if that is the same gun used to kill Officer Preston.

We spoke to that driver, who says police surrounded his car within moments of the passenger getting in.

"All I saw like a minute after that was lights and police personnel jumping down from their cars, surrounding my car from the back with their guns pointed at my vehicle," said the driver.

The shooting suspects are also linked to a string of robberies that occurred before the shooting.

Video taken by the Uber driver, who did not want to be identified, showed the moments after two of his passengers were taken into custody around 7:30 p.m. Sunday. Police reports said at least one of those passengers was wanted in connection with the murder of Officer Preston.

A gun was recovered, but it was unclear if it was the same weapon used to kill Preston.

The driver, who did not want to be identified, said he was initially placed in handcuffs. But as soon as officers sorted the scene, they took the handcuffs off the driver.

"I just started screaming: 'I'm just an Uber driver! I don't know what's going on!" the driver said. "All I saw like a minute after that was lights and police personnel jumping down from their cars, surrounding my car from the back with their guns pointed at my vehicle."

According to police reports, CPD surveillance teams were monitoring the murder suspect – who got into the Uber near 76th and Bishop streets. The driver said within a minute, heavily-armed officers surrounded his car.

Other suspects connected to the shooting were also taken into custody near the same intersection in Auburn Gresham after a SWAT standoff in a building.

"I'm just in shock," the Uber driver said. "I'm just wondering how I found myself in this kind of situation."

The Uber driver was not injured.

Meanwhile, the shooting suspects are also linked to at least one armed robbery that occurred before the shooting.

Police reports show the suspect arrested in the Uber was also wanted in an armed robbery that occurred early Saturday morning near 46th Street and Ellis Avenue in Kenwood.

Police also quickly linked a specific red car to Preston's homicide. The car was later found torched and abandoned near 73rd Street and Eberhart Avenue in Grand Crossing.

So between a series of armed robberies and Preston's homicide, Chicago Police worked very quickly to try to connect all the dots and find everyone involved. At this point, formal charges have not been announced.

Officer Preston was set this coming weekend to graduate from Loyola University School of Law with a Master of Jurisprudence.

While Chicago Police are not confirming what led to Preston's murder, the Fraternal Order of Police posted a reaction to its Facebook page that Preston was "killed while trying to defend herself from armed individuals in an apparent robbery [and] she died taking police action."

A procession was held Tuesday morning as Preston's remains were carried from the Cook County Medical Examiner's office, 2121 W. Harrison St., to the Blake-Lamb Funeral Home, at 4727 W. 103rd St. in Oak Lawn.