A Texas man accused of killing his ex-girlfriend’s father has now been tied to at least three shooting deaths in the last few weeks in what authorities are calling a random crime spree that is “the definition of a serial killer.”

Jeremy Harris, 31, has been charged for a string of killings that began on Halloween and ended with his arrest on Wednesday for the murder of 60-year-old Blair Carter, who was found inside a house set ablaze.

The Celina Police Department said Harris is facing charges for at least three shooting deaths in Dallas, including the murder of 19-year-old SMU student Robert Jaden Urrea, who was waiting for a rideshare after a Halloween party. The other two victims, who were shot on Nov. 14, were 36-year-old Adam Gautreau, who was hit on a street corner, and 57-year-old Kenneth Jerome Hamilton, who was struck from inside his car at a red light.

Authorities say that, during each random shooting, Harris pointed a gun from the window of his driver’s seat, fired, then drove off.

“I believe this is the definition of a serial killer,” Dallas Deputy Chief Reuben Ramirez said, adding that besides Carter’s death in Celina, there was no known connection between Harris and his victims.” “The characteristics of the shootings are similar, he’s always shooting out of a vehicle.”

Harris’ arrest ended a massive manhunt for the person behind the terrifying shooting spree. The investigation included a plea for the public’s help and assistance from the U.S. Marshals’ North Texas Fugitive Task Force.

Dallas Police Chief U. Reneé Hall said Friday the surge of shootings after Halloween was particularly alarming because “it was separate and apart from anything that we’ve seen.”

“The knowledge that someone is randomly, with no real reason and reckless regard for human life, going around murdering individuals is a separate kind of fear,” she said.

Authorities allege Harris shot Urrea from a white Ford Taurus just after the 19-year-old had called a rideshare around 3 a.m. on Oct. 31. The arrest affidavit says he appeared to summon Urrea to the passenger side of the car before shooting and speeding off.

On Thursday, Dallas police found that car—later identified as belonging to Harris’ girlfriend—in a repair shop. Inside, investigators found a bullet cartridge under the passenger seat. The arrest warrant says Harris had been involved in a car accident hours after Urrea’s killing.

“We are grateful for the arrest of a suspect in the murder of our student, [Robert] Jaden Urrea,” Dr. K.C. Mmeje, vice president for student affairs at Southern Methodist University, said Friday. “While nothing can ease the pain felt by his family and friends, we sincerely hope the successful prosecution and conviction of Jaden’s killer will allow them to find peace.”

On Nov. 14, Harris allegedly shot Gautreau several times from a black Chevy Tahoe. Gautreau’s mother told WFAA that her son was panhandling when he was summoned to the car—before he was shot multiple times as the driver fled. About 40 minutes later, Hamilton was found dead in the driver’s seat of his car. Police say he was shot while waiting at a red light.

“Innocent people are being killed for no reason,” Hamilton’s wife, Joyce, told WFAA at the time. “I don’t care where you go, you need to be aware of your surroundings, because people are killing senselessly.”

On Wednesday morning, Celina Fire Department crews responded to reports of a home on fire. After extinguishing it, they found Carter’s body. Witnesses told police they heard what sounded like gunfire inside the home before a man dressed in black ran from the house with an unknown object. They also described seeing a black Chevy Tahoe—the same car model used in at least two of the Dallas shootings.

According to court documents, after Harris was arrested on Nov. 17 in connection to Carter’s murder, Dallas police linked a gun found in his possession, as well as his Chevy, to the shootings. Authorities also used video surveillance to connect Harris to the crimes.

Later, when police search his apartment, they found black rims he had removed from his SUV days before the arrest—which were captured in images being circulated by news outlets.

“We really started to find the pieces,” Ramirez, the deputy police chief, said. “Through collaboration with our federal partners, as well as the municipalities in this region… we really started to piece this thing together.”

Harris is being held at Ellis County jail on a $3 million bond.