MUKILTEO, Wash. -- Mukilteo shooting suspect Allen Ivanov told investigators that he purchased an AR-15 semi-automatic rifle about a week before the murders and used the weapon to shoot and kill his “dream girl” and two other young men in a burst of anger, according to court documents released Monday.

“Ivanov stated that everything that went on tonight was about a girl,” wrote Detective John Ernst, a detective with the Mukilteo Police Department, who interviewed Ivanov hours after the shooting.

The documents also state that a few days before the shooting Ivanov sent text messages to someone in Kentucky regarding committing a mass shooting.

<p>***File image*** Mukilteo shooting suspect Allen Ivanov makes his first court appearance in Snohomish County. (Credit: KING)</p>

Ivanov, 19, told police he had dated 19-year-old Anna Bui for about a year and a half and broke off the relationship roughly two months ago because he felt he needed time to work on himself.

Following the breakup, Ivanov kept getting “hurtful” Snapchat social media messages from Bui, indicating that she was getting on with her life without him, Detective Ernst wrote.

Ivanov, realizing he made a mistake, decided he wanted to get back with Bui, and the two spent some time together during the week before the shooting, the documents state.

“He thought things were going well,” Detective Ernst wrote.

Ivanov became angry when he heard from peers that Bui was seeing other guys, the narrative states.

He said he purchased a Ruger AR-15 semi-automatic rifle about a week before the attack with the intent of using it for target practice. Ivanov said he planned to attend a gun safety class in August. He admitted to investigators that “the rifle was a symbol of power.”

Ivanov's Attorney Tim Leary questioned the ease of him buying such a dangerous weapon.

“Someone who is 19 years old can't go out to a bar, can't buy a beer, yet he can walk into a gun shop and in 30 minutes buy a AR 15, with a high capacity clip and that's okay? I think it raises questions in our case, and questions in the community,” he said.

On Friday, the day before the shooting, Ivanov said he left his job at the Alderwood Mall Apple Store early because he wasn’t feeling well. He said he proceeded to the Cabela’s store in Marysville and bought a second magazine for his rifle because he thought he would need two magazines for his class.

According to the detective’s written statement, Ivanov showed up to the house in the 10000 block of Chennault Beach in Mukilteo around 10 p.m., Friday, parked across the street, and watched. He told investigators he crept up to the house and saw an individual, referred to in the court document as “A,” with another male and got angry.

Ivanov returned to his car, read the instruction manual for the rifle, loaded the magazine, prepared the rifle, and crept around the side of the house, where he hid along a wall near the living room.

A male partygoer discovered Ivanov, the documents state.

“No, no, no," the male said, according to Ivanov’s statement to investigators. Ivanov, who said he was “scared,” shot and killed the male.

Ivanov told investigators that “at that point, it was too late to turn back, and once he had pulled the trigger his adrenaline kicked in.”

The shooting suspect entered the house, found Bui, and shot her twice. He said he went further into the house and shot a male before going upstairs and onto a balcony off of the master bedroom where he fired down at two more males in the driveway.

Ivanov said he went to the roof and realized his magazine was empty. He returned to his car and drove away.

He was taken into custody by Washington State Patrol in Lewis County, aided by Lewis County Sheriff's office and Chehalis Police. Officers pulled Ivanov over for speeding on southbound Interstate 5 in a 2016 Subaru WRX and transported him back to Snohomish County, where investigators interviewed him.

Ivanov's Attorney Zach Wagnild described his client as being just a kid.

“This is not a sophisticated person, if you think someone is sophisticated, they would do things, they would cover it up, and they wouldn't talk and they would play the system. But that's clearly not the case, you saw him he looked like a 14 year old boy in there,” he said.

Detectives also spoke over the phone with a witness from Kentucky, who told them that Ivanov was sending text messages to him regarding committing a mass shooting two or three days ago. A detective viewed the messages and verified their existence.

Ivanov made a brief first court appearance Monday afternoon; a judge ordered he be held without bail and that he have no contact with the victims' families.

Wagnild said Ivanov’s parents are distraught by the situation.

“They were very close with Ms. Bui, his girlfriend, they loved her. And they said they have a huge amount of remorse, not just for their son, but for all the families here and the young people involved.”