Sharif Austin was getting ready to spend his first Christmas as a father.

Monserret Noyola-Narvaez was studying to become a nurse.

Neither would see those plans through. Both were shot and killed separately during a six-month span of violence that began as revenge for a Somerset murder, authorities say.

The gunman behind the violence was Kerron Parker, a 19-year-old arrested earlier this month on charges he killed Austin, who was 21.

Once in custody, Parker was also charged with two different attempted murders last summer, and with murder for Noyola-Narvaez’s killing in October. Authorities now believe her death - she was driving in her car - was a case of mistaken identity.

The crimes are all shootings, and Parker may have been involved in a fifth one, in New Brunswick, court documents say.

Parker’s alleged wave of gunplay was fueled by his desire for revenge after a friend of his was murdered last spring, witnesses told police.

Parker’s friend, David Anderson, was shot and killed during a May 2019 gathering at a Franklin Township park. Witnesses to Parker’s shootings told police he wanted to avenge his friend’s death, authorities allege.

But none of the people targeted in Parker’s alleged quest for revenge were charged in connection to Anderson’s death.

While family members said Austin and Parker had "beef” with each other, Noyola-Narvaez was not the target of the October shooting that killed her, officials said in court documents.

An arrest has been made in Anderson’s death: Najee K. Croom, 27, of New Brunswick, also known as “Na Murder,” was charged with murder in November. He remains in the Middlesex County Correctional Facility.

Parker’s alleged crimes began on July 18, when Parker and some friends drove into a neighborhood behind New Brunswick High School, court records say.

Parker began firing when he spotted a man from Robeson Village, the nearby apartments called “the Ville” by locals, records show. It’s not clear if an armed, backseat passenger fired any shots during the crime.

The second shooting on Aug. 22 unfolded almost identically, near the 101 Zebra Way apartments in New Brunswick.

Both Parker and a backseat passenger began shooting when they saw the same person, who targeted in July, walking with a woman, officials said. The person they fired at was not charged in connection to Anderson’s death, court records show.

It’s unclear if anyone was wounded in those two shootings, but Parker is charged with attempted murder for each incident.

It’s not clear if the driver was the same person on both days, but the driver told police who Parker was looking for in both cases. The drivers’ name is redacted on two affidavits of probable cause filed by investigators.

Exactly two months later, Parker is accused of committing his first murder in neighboring Franklin Township.

Parker, who is from the Somerset section of the town, stood in the grass outside a Matilda Avenue apartment complex and shot into a car, records show.

The driver, Noyola-Narvaez, was found injured behind the wheel of her car the next street over, police said. She died from her injuries at Robert Wood Johnson University Medical Center several days later.

Court records do not give a motive for the shooting, but the Somerset County Prosecutor’s Office has called it a possible case of a mistaken identity in statements.

Deputy Chief Frank Roman, with the Somerset County Prosecutor’s office, declined to elaborate on the mistaken identity aspect, citing an ongoing investigation. He said Somerset officials were working closely with officials in Middlesex to determine if the shootings are all connected.

Another two months later, Parker is accused in the final shooting of the alleged spree. Parker and a friend drove into New Brunswick from Highland Park, ostensibly to stop by a convenience store.

Instead of heading into the store, Parker is accused of getting out of the car to shoot Austin at close range. Parker was driven back to Highland Park with the gun in his lap, the driver told police.

Austin died early the next morning at a nearby hospital, on Christmas Eve.

Austin’s family told investigators Austin had "beef” with two people, including Parker, at the time of his death. The name of the second person involved in the dispute was redacted from documents.

Parker was arrested at his Somerset home on Jan. 2, and charged with murder and weapons offenses. He is currently detained at the Middlesex County Correctional Facility.

A fifth shooting linked to Parker does not appear to have resulted in any injuries.

Bullets that matched those from the July, August and December shootings were found on Suydam Street in New Brunswick on Sept. 21, court records show. City police responded to a shots fired report on Suydam Street early that morning, New Brunswick Today reported.

Police in New Brunswick did not respond to NJ Advance Media’s request for more information about the cases.

Katie Kausch may be reached at kkausch@njadvancemedia.com. Follow her on Twitter @KatieKausch. Find NJ.com on Facebook.

Have a tip? Tell us: nj.com/tips. Get the latest updates right in your inbox. Subscribe to NJ.com’s newsletters.