Timeline: How the string of murders of 4 Muslim men in Albuquerque unfolded

Albuquerque police have arrested a suspect in connection with the murder of four Muslim men in the past nine months.

Muhammad Atif Syed, a 51-year-old man originally from Afghanistan, has been charged with two of the murders, while investigators are left to gather enough evidence to possibly charge him with the remaining two.

"We think there might be involvement in two other homicide cases," Albuquerque Deputy Cmdr. Kyle Hartsock told reporters during a news conference Tuesday. "Those are still considered open and active."

The motive behind the shootings is unclear, Albuquerque police said during the press conference, adding that there are no indications yet that the murders were carried out by a serial killer or are the result of a hate crime.

This is how the possible string of murders of the four Muslim men unfolded:

Several years ago

Syed moved to the U.S. from Afghanistan.

2018

Syed was arrested multiple times on misdemeanor domestic violence charges, authorities said during Tuesday's news conference. Those charges were later dismissed.

Jan. 28, 2021

Syed purchased an XD-M 9mm pistol, according to a criminal complaint against Syed filed in Bernalillo County on Tuesday.

Nov. 21, 2021

Mohammad Ahmadi, a 62-year-old Muslim man from Afghanistan, was killed outside a business he ran with his brother, police said.

Ahmadi was found dead after he was shot near San Mateo Boulevard and Mountain Road in Albuquerque's Fair Heights neighborhood, ABC Albuquerque affiliate KOAT reported.

Syed may have had a personal connection to Ahmadi, and the patterns from his murder match the others, police said during Tuesday's news conference.

May 28

Syed purchased a new hammer for his AR-15-style rifle from Roof Korean Custom Gunsmithing, a gun repair and parts store in Albuquerque, the manager told police, according to the charging document.

July

Syed and his son, Shaheen "Maiwand" Syed, both purchased AR-15-style rifles from BMC Tactical, a weapons store in Albuquerque, according to the arrest affidavit.

July 26

10:02 p.m.: Police receive a notification from ShotSpotter, a gunfire locator service, near 417 Rhode Island St. NE in Albuquerque's Trumball Village neighborhood, according to the criminal complaint. Comments on the ShotSpotter notification indicated that more than 13 rounds were fired, the arrest affidavit states.

10:07 p.m.: Officers were dispatched to the address, when they found Aftab Hussein, 41, lying next to a silver Hyundai sedan at 420 Rhode Island St. NE, according to the complaint.

Hussein was pronounced dead at the scene after sustaining multiple gunshot wounds, and 7.62x39 casings were found on the scene, the affidavit states.

The suspect allegedly waited behind a bush north of the driveway where Hussein would park his vehicle and shot Hussein multiple times, through the bush, as he exited the car, police said, citing evidence located at the scene of the shooting.

Hussein is originally from Pakistan, according to police.

Aug. 1

Syed purchased a scope for his AR-15-style rifle from Roof Korean Custom Gunsmithing, the manager told investigators, according to the criminal complaint. Surveillance footage taken from the store shows Syed and one of his sons exiting a grey Volkswagen Jetta and entering the store, the arrest affidavits states.

Before going to Roof Korean, Syed and his son, Shaheen "Maiwand" Syed, went to Omni Arms, another gun shop in Albuquerque, according to the criminal complaint. The scope that Syed bought at Roof Korean was for the gun he bought at BMC Tactical in July, Shaheen "Maiwand" Syed told investigators, the charging document states.

9:17 p.m.: Emergency dispatchers received a 911 call near Cornell Drive and Garfield Avenue in Albuquerque's Victoria Hills neighborhood, according to the criminal complaint. The caller stated that there were multiple gunshots in the area and that they believed there had been a "drive-by" shooting, saying that the vehicle sped away after the gunshots were fired, the affidavit states.

9:19 p.m.: Officers are dispatched to 420 Cornell Dr. SE., according to the complaint.

9:20 p.m.: Emergency dispatchers receive three ShotSpotter activations, which indicate that about 15 shots were fired on Cornell Drive, the charging document states.

9:23 p.m.: Emergency dispatchers receive 911 calls from multiple people detailing a shooting near 422 Cornell Street and that someone appeared to be shot on the sidewalk, according to the arrest affidavit.

9:27 p.m.: Officers arrive on the scene and find Muhammad Afzaal Hussain, 27, dead from multiple gunshot wounds, the charging document states. Investigators found seven 9mm casings and seven 7.62x39 casings, according to the complaint.

Muhammad Afzaal Hussain is originally from Pakistan, police said.

Aug. 2

10:38 a.m.: While meeting with the family of Muhammad Afzaal Hussain at the Family Advocacy Center, investigators learn that he and his family routinely take walks around the neighborhood from 9 p.m. to 10 p.m., the arrest affidavit states.

Muhammad Afzaal Hussain's brother saw him using his cell phone as he left the apartment, located at 402 Cornell Drive SE, on the night of the shooting, according to the charging document.

12:53 p.m.: A witness who was across the street when the shooting occurred tells investigators she saw a dark silver or grey four-door sedan pull up to the east side of 422 Cornell Dr. SE and flee the area after the gunshots stopped, the arrest affidavit states.

3:38 p.m.: A friend of Muhammad Afzaal Hussain's told police they were speaking over FaceTime around 8:35 p.m. on Aug. 1 when he got another call -- that he had an issue and had to answer, according to the charging document.

Aug. 3

Investigators learned that the murders of Hussein and Muhammad Afzaal Hussain were likely linked after a National Integrated Ballistics Information Network review of the 7.62x39 casings from both scenes determined that they were fired from the same gun, the criminal complaint states.

Friday

Naeem Hussain, a 25-year-old native of Pakistan, was found dead from a gunshot wound near Truman Street and Grand Avenue in Albuquerque's Highland Business neighborhood, police announced on Saturday, linking Naeem Hussain's death to the recent murders of three other Muslim men in Albuquerque.

The Albuquerque Police Department's homicide unit began noticing similarities between the murders that occurred on Friday and July 26, such as related shell casings found at both scenes that were likely fired from the same gun, Hartsock said.

Sunday

Albuquerque Police released a wanted poster with an image of a silver or grey Volkswagen sedan they believe was used in the murders.

Monday

The Albuquerque Police Department and the FBI begin to receive multiple tips they say point to Syed.

The callers also stated that Syed drives a gray Volkswagen sedan and lives in an apartment on Crest Avenue in Albuquerque's Southeast Heights neighborhood, the arrest affidavit states.

10:59 a.m.: Investigators identified Syed as he exited his apartment and drove to Costco in a gray 2015 Honda sedan, which did not have a license plate, according to the criminal complaint.

12 p.m.: Syed returned home.

1 p.m.: Investigators located a gray Volkswagen Jetta in front of Syed's apartment, according to the charging document.

1:43 p.m.: Investigators interviewed Syed's sons and managers at multiple gun stores about Syed's firearms purchases, the arrest affidavit states.

11:29 p.m.: Syed left his apartment and drove east on Interstate 40 in the gray Volkswagen Jetta, according to the criminal complaint. New Mexico State Police performed a traffic stop and arrested Syed near Santa Rosa, New Mexico -- about 115 miles east of Albuquerque.

Syed had a gun inside his car at the time of his arrest, police said during Tuesday's press conference.

Tuesday

1:15 a.m.: Investigators executed a search warrant on Syed's apartment, where they found two rifles -- one in his bedroom and another in his son's room, according to the charging document. Both rifles were collected and test-fired.

One of the guns found at Syed's home matched shell casings from one of the crime scenes, police said Tuesday.

6:29 a.m.: Authorities interviewed Syed's son, Shaheen "Maiwand" Syed, at the police station, the arrest affidavit states.

6:45 a.m.: A search warrant was executed on the Volkswagen, in which a 9mm shell casing was found between the windshield and the hood.

8:24 a.m.: The test fires from the rifle found in Syed's apartment indicate that the 7.62x39 shell casings located at the murder scenes for Hussein and Muhammad Afzaal Hussain were fired from that gun, according to the criminal complaint.

9:05 a.m.: During an interview at the police station, Syed told officers that the 2017 Volkswagen Jetta was initially purchased by his 23-year-old son, Adil Syed, but that he purchased it from him and it is now his vehicle, the arrest affidavit states. Syed allegedly admitted to police that the gun found in his car is his and that he also owns an AR-15-style rifle that he keeps in a cardboard box under his bed, according to the charging document.

Syed told officers he was driving to Houston to find a new place for his family to live because "the situation in Albuquerque is bad," referencing the shootings of Muslim men that had been circulating through the news, according to the charging document. Syed said he took clothes, shoes and a firearm, the document states.

Syed told investigators that he sometimes takes his son, Shaheen, to the desert to shoot the AR-15-style rifle, an act he referred to as "hunting," according to the charging document.

Syed also allegedly stated that he used to be with Special Forces in Afghanistan and that he fought against the Taliban, according to the affidavit.

Syed denied having any involvement in the murders but told police that he has known Naeem Hussain since 2016 and that he had recognized Aftab Hussein from parties in the community, according to the criminal complaint.

It is unclear whether Syed has retained an attorney.

11:42 a.m.: A lead from the National Integrated Ballistics Information Network linked the handgun found in the Volkswagen with a 9mm shell casing found between the windshield and hood of the car, the arrest affidavit states.

ABC News' Marilyn Heck and Alyssa Pone contributed to this report.