MARYSVILLE — Minutes before a teenager opened fire inside a Marysville Pilchuck High School cafeteria, he sent a text message to more than a dozen relatives describing what he wanted to wear at his funeral.

The text message included a detailed list of who should get his personal possessions. Jaylen Fryberg, 15, also asked relatives to apologize to the families of his friends “who get caught up in the (expletive) tomorrow” — referring to the day after the shooting.

The Tulalip teen, recently crowned freshman homecoming prince, earlier sent a text to his friends, arranging to meet them for lunch Oct. 24. The victims were seated at the table when he opened fire with a .40-caliber Beretta handgun.

Killed were Gia Soriano, Zoe Galasso and Shaylee Chuckulnaskit, all 14, and Andrew Fryberg, 15. All were shot in the head.

Nate Hatch, 14, was shot in the jaw. He is recovering at home.

The details of Jaylen’s last text messages — but not their full contents — were described by an Everett police detective in a search warrant affidavit, obtained Wednesday by The Daily Herald. The detective is part of the Snohomish County Multiple Agency Response Team assigned to investigate the school shootings. He was seeking a judge’s permission to examine Jaylen’s cellphone.

Detectives have been poring over hundreds of text messages and social media posts since the violence. The medical examiner found the cellphone in Jaylen’s pocket.

The Everett police detective included in the warrant affidavit some text messages from Jaylen that indicate that he might have been planning something days before the shootings. The warrant says the detectives were searching for evidence of first-degree murder.

Jaylen had publicly posted some angry messages on social media starting in late July, but his posts otherwise were “pretty normal,” the detective wrote. Starting Oct. 18, however, his text messages took a darker turn.

Detectives learned that Jaylen had been upset by something that happened between him and a 15-year-old who is identified in the affidavit only by her initials and described as a “close friend.”

Investigators know what happened between the two but decided against including specifics in the search warrant to protect her identity, court papers said.

On Oct. 18 Jaylen sent this text:

“Ohk (sic) well don’t bother coming to my funeral”

The girl stopped responding and ignored other text messages.

Then on Oct. 22, Jaylen texted:

“I set the date. Hopefully you regret not talking to me”

“You have no idea what I’m talking about. But you will”

“Bang bang I’m dead”

The friend asked Jaylen to quit. He replied, “No. You don’t care. I don’t care.”

When she stopped responding Jaylen tried to reach her through another friend.

On the morning of the shootings, Jaylen used Facebook to send that friend a picture of a gun sitting between his legs, according to the search warrant. He told the friend to have the other girl “call me before I do this.” The message was sent about 10:25 a.m., minutes before Jaylen began shooting.

The gun in the photograph appears to be the same weapon detectives found lying on a table in the cafeteria after the shootings.

The search warrant doesn’t mention whether any other students were invited to lunch that day.

Detectives also investigated rumors that students had gone to a teacher or principal the day before the shootings and expressed concerns about Jaylen. Marysville Pilchuck is a school with 1,200 students.

There is nothing to support that rumor, SMART spokeswoman Shari Ireton said Wednesday.

“We have not been able to find a shred of evidence” of that, she said.

Investigators have spoken with dozens of people who were in the cafeteria that morning. The Everett detective spoke with two students who were eating lunch when the gunfire began.

“They looked up and observed Jaylen Fryberg standing at a table ‘calmly’ shooting other students,” the search warrant said.

Nate Hatch told investigators he was eating lunch when Jaylen stood up and started shooting. Jaylen fired at Nate. The bullet entered near his chin and traveled through his body, lodging in the strap of his backpack, the search warrant said.

When the detective joined others collecting bullet fragments and other evidence inside the cafeteria, the bodies of Jaylen and one of his victims, Zoe Galasso, had not yet been moved.

Jaylen was on his back, with his wrists secured in handcuffs. There was a gunshot wound below his chin. An autopsy later determined his death was a suicide.

The handcuffs were snapped in place by one of the first police officers on the scene — standard practice when securing the scene of a violent crime.

The day of the shootings, the Everett police detective met with two of Jaylen’s uncles. One asked the detective if he had seen the text.

The man said he and 13 other relatives received the message from Jaylen minutes before the shootings. The text was titled “My Funeral (expletive).”

The detective later went to speak with the boy’s parents. He was met by Tulalip police officers, who explained that the couple had received death threats and weren’t at home.

His father returned home and cooperated with investigators, allowing the detectives to search Jaylen’s bedroom.

“My hope was that we could find a note or something that would help explain what happened,” the detective wrote. “Nothing of evidentiary value was located in Jaylen’s room.”

Diana Hefley: 425-339-3463; hefley@heraldnet.com. Twitter: @dianahefley