After a month of piecing the bizarre crime together, investigators believe it began on the night of February 1, when Perez shared a Facebook Live video inviting people to her apartment for $500 "tap-out" tattoo sessions, explaining that you get as many tattoos as you can bear.
"There's tats going on over here guys," she said in the video, per NBC DFW. "Whoever wants to get tatted up. My favorite and best tattoo artist is here. But you have to come with money."
When questioned by police, 28-year-old Perez admitted Alhassinyani had been at her apartment that night, but she kicked him out around midnight after they had an argument.
Detectives said when they told her he had been found murdered, she didn't seem surprised, sad, or even curious.
When they tracked down and interviewed the tattoo artist however, he told a very different story.
The artist, who is not charged with any crime, said he was giving a tattoo to a man he only knew as "Puppet" when Alhassinyani and Perez got in an argument; he said she got angry ripped his shirt and put tape over his mouth.
Going through Perez's phone, detectives found a disturbing video which placed Alhassinyani at the apartment at 5:42 AM — much later than his girlfriend claimed he left.
The arrest warrant describes the footage: "Puppet" — later identified as Benjamin Delgadillo — holding a gun, forces a shirtless Alhassinyani to lay face down on a massage table.
Delgaldillo, 21, then took the tattoo gun, according to the warrant, from the artist and began defacing the tattoo Alhassinyani already had on his back: logo of the city of Arlington with the words "South Side" on each side.
"That is nice ass work," Delgadillo said as he scribbled over it, according to authorities. "I am a real ass (expletive) from the south cuz."
Alhassinyani pleaded with him to do it softer, but Delgaldillo ran "the tattoo gun harder over his back" the detective wrote.
"Ouch," Perez can be heard saying on the video. "Loyalty hurts more."
"Hey, my bad," Delgadillo is said to have replied, "I am not a professional tattooer."
The artist claimed Perez then told him to tattoo her name on Alhassinyani; he told the detectives he was just there to make money and didn't want any trouble and, knowing Delgaldillo was armed, he did it as quickly as he could.
He told the investigators that three other armed men then showed up at the apartment, and Delgaldillo let them in.
"Can I just call my mother to take me home?" Alhassinyani asked. "We will take you home," one of the gunmen is said to have replied.
After being arrested, Delgadillo gave "multiple stories", before he eventually confessed, police said. He said that after taking her boyfriend's wallet and phone, Perez handed it to one of the gunmen and said: "Whatever you do to him, don't do it here."
The four men then loaded into a Dodge Challenger and drove him to Euless, where they stopped and ordered him out of the car. He initially refused, but they forced him.
Delgadillo said one of the men, Justin Jaxs Salinas, then pulled out a Glock pistol and shot him once in the neck.
They fled in the car, but returned later to drag the body away from the highway to a nearby creek, per police docs. He was not found until two days later.
Delgadillo, Salinas, and the driver Pedro Rodriguez are all charged with capital murder. Police have yet to apprehend the fourth gunman, but they believe they know his identity.
Each of the three have varying criminal records: Rodriguez, 21, had previously been charged with a knife murder at just 16 — while already on probation for various other crimes — but was ultimately not indicted.
Salinas was wanted for robbery and drug possession when he was arrested for Alhassinyani's murder.
Delgadillo has the shortest record of the three, having spent only one night in jail following a marijuana possession arrest.
Perez meanwhile, who has string of arrests dating to 2012 for drug possession and theft, has not been charged with murder. Instead she was booked for aggravated assault with a deadly weapon, kidnapping, failure to report a felony, and making a false report to police.
The tattoo artist has not been charged at all; he told detectives he didn't even know Alhassinyani had been killed until he saw a news report.