A homicide suspect from Arizona, believed to be a serial killer, was accused of killing nine people in a three-week span, including his mother and stepfather.

Cleophus Cooksey Jr. was arrested after fatally shooting his parents in Phoenix on Dec. 17, however, further investigation revealed that he might be responsible for the deaths of seven other people. Addressing a press conference in Phoenix on Thursday, police said the 25-year-old Cooksey Jr. went on a murder spree between Nov. 27 and Dec. 17, 2017, in Phoenix and the nearby suburbs of Glendale and Avondale.

"Our detectives didn't stop there, they kept digging," Phoenix Police Chief Jeri Williams said. According to the Arizona Central, the killings lacked a unifying pattern or method and included victims from several demographic groups. The only clear connection among the victims was Cooksey Jr. who had a criminal record dating back to the time of him being a juvenile offender.

The police credited the use of new technology implemented as part of the National Crime Gun Intelligence Center for the discovery. Reports said that the high-powered in-house technology was used to compare bullet casings from Cooksey Jr.'s gun along with multiple crime scenes. Apart from the murder of his mother and stepfather, Cooksey Jr. was also accused of abducting a woman in Glendale on Dec. 15, sexually assaulting and killing her, and later dumping her body in south Phoenix. Among Cooksey Jr.'s victims was the brother of his former girlfriend. However, other victims appeared to be random.

The alleged spree began on Nov. 27 when Phoenix police found the bodies Andrew Remillard and Parker Smith who were shot to death in a vehicle. On Dec. 2 another man, Salim Richardson, was found dead of a gunshot wound. The suspect in Richardson’s murder had allegedly fled the scene and after stealing the victim’s handgun.

During the investigation, police came across a man named Jesus Real who was also shot dead from a gunshot wound inside an apartment complex in Avondale on Dec.11. In this case, too, the suspect had fled the scene. It was then discovered that Real’s sister was Cooksey Jr.’s former girlfriend. It was then the police connected Cooksey Jr. to the murder.

On Dec. 13, police responded to a shooting in a Glendale apartment complex and found LaTorrie Beckford, who died soon after. A few days later, on Dec. 15, the police discovered another victim named Kris Cameron in Glendale who too died of a gunshot wound. While investigating the case, police said Cameron might have been in the area for a drug deal with Cooksey Jr. The following morning, the body of a woman named Maria Villanueva was found in Phoenix, Arizona. Police said Villanueva was the same woman Cooksey Jr. had kidnapped in Glendale and sexually assaulted and killed her.

On the evening of Dec.17, police were called to his mother’s house following reports of gunshots by witnesses. "The officer did not see any casings or blood trail leading from the apartment, which made him believe the injured person may still be inside the apartment," court documents said, according to CBS-affiliate KPHO. Cooksey Jr. answered the door when an officer knocked and grew agitated when the officer decided to detain him.

"Cooksey became upset and began yelling, 'I'm the strongest man alive,' and 'I'll cut your throat,' and 'I control the gun,'" the probable cause statement said. His parents’ bodies were found in the apartment following his detention.

"I'm just proud as heck that he's off the street," said Glendale police Chief Rick St. John.

Phoenix Mayor Greg Stanton said:: "Our streets are safer today.” Cooksey Jr. pleaded not guilty to the crimes pressed against him.

Investigators recommended that Cooksey Jr. be charged with seven additional murder counts, along with charges of prohibited possession of a firearm, armed robbery, and sexual assault. The Maricopa County Attorney's Office was yet to make formal charges.