Palo Alto police have arrested one of four young men suspected of stealing from vehicles in three south Palo Alto neighborhoods and then firing upon a resident who confronted them.

The incidents happened on Jan. 29 shortly before midnight. A resident in the 3600 block of South Court had noticed lights shining in the street outside his home and saw multiple people walking down the street with flashlights. They appeared to be shining the lights into parked cars and trying to open car doors.

The resident went outside to confront them and found a person standing by the open driver's door of his car in the driveway. He chased the thieves on foot as they ran to a waiting getaway SUV. The man heard what sounded like a gunshot and thought he saw the impact of the round on the pavement in front of him.

He was not hit by the gunfire and never saw the weapon, police said. But officers who responded to the resident's 911 call later located an expended casing from a .40-caliber handgun at the scene and processed it for evidence.

A check of the neighborhood found that at least two other unlocked cars on South Court had been rummaged through. Within the hour, at 12:45 a.m., police received another call from a resident, this one who lived in the 700 block of Talisman Court in the Palo Verde neighborhood. That resident had reviewed surveillance camera footage and saw a group of people had rummaged through unlocked vehicles at 11:20 p.m.

Detectives conducted an extensive follow-up investigation in the case and were eventually able to identify the suspects, three of whom are juveniles, police stated on Thursday in a press release.

Detectives have developed information to support charging the four with petty theft from auto and conspiracy, but the investigation into which of them held the firearm and fired the shot remains ongoing, police stated.

The firearm has not yet been recovered. Detectives also identified the vehicle used in this crime as a red 2015 Jeep Grand Cherokee that had been stolen earlier on Jan. 29 in San Jose and that was found in Morgan Hill around 10 a.m. on Jan. 30.

Inside the vehicle, police located property that had been stolen from an unlocked vehicle on Alma Street in Palo Alto near the time of the shooting.

On March 16, detectives arrested a 15-year-old boy from San Jose who was the driver of the vehicle for conspiracy, possession of stolen vehicle and accessory to assault with a deadly weapon (all felonies), as well as petty theft (a misdemeanor).

At the time of the arrest, he was in custody at the Santa Clara County Juvenile Hall on an unrelated offense.

Police have not located the other two juvenile suspects — another 15-year-old boy and a 17-year-old male, both from San Jose — and are requesting charges be brought against both of them for conspiracy (a felony) and petty theft (a misdemeanor).

The fourth suspect is an 18-year-old male from San Jose, and detectives are requesting the District Attorney's Office to review the case against him for appropriate charges, which could include conspiracy, possession of stolen vehicle, accessory to assault with a deadly weapon and petty theft.

Mothers Against Murder, a local nonprofit organization, has offered a $20,000 reward in the case. That reward remains unclaimed and is still available, should someone provide information leading to the arrest and conviction of the shooter. More information is available at mothersagainstmurder.org and 650-285-9221.

Police are asking that anyone with information about this case call the department's 24-hour dispatch center at 650-329-2413. Anonymous tips can be emailed to paloalto@tipnow.org or sent via text message or voicemail to 650-383-8984.