A friend from middle school said Gonzalez was depressed and would call her at night

Gonzalez had been suicidal and allegedly killed Middleton to see how people will react, source said

Adrian Gonzalez, 15, made his first court appearance today to face charges of murder and sexual assault in connection to 8-year-old Maddy Middleton's slaying as it emerged that the teenager allegedly lured the child to her death with ice cream.

Gonzalez briefly appeared at the Santa Cruz County courthouse but did not enter a plea. His arraignment was pushed back to September 21.

The teenager is being charged as an adult in connection to Middleton's death at the Tannery Arts Center housing complex over the weekend.

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In court: Adrian Gonzalez, center, is flanked by public defender Larry Biggam and attorney Leila Sayar as they enter the courtroom Thursday, July 30, 2015 where his arraignment was delayed in Santa Cruz

In the lead-up to Gonzalez’s first court appearance, a source revealed to the San Francisco Chronicle that that the suspect, who was Maddy's neighbor, drew her to his third-floor apartment with the promise of ice cream.

Once the girl was inside, Gonzalez allegedly restrained her from behind, tied her up with duct tape and raped her before strangling the child to death.

While police have not said anything about a possible motive, the source claimed that Gonzalez had been suicidal and allegedly killed Maddy because he wanted to see how people would react.

Katie Carole, a friend of Gonzalez’s from middle school who attended his first court appearance today, told San Jose Mercury that the boy she knew simple as ‘A.J.’ was quiet and shy, but depressed.

She recounted that before she broke off their friendship two years ago, Gonzalez would call her in the middle of the night and threaten to jump off the roof.

Carole said that both she and her mother tried to convince Gonzalez to get psychiatric help.

After learning of the allegations against the rising high school sophomore, Carole went through Gonzalez’s text messages to her, one of which read: ’I’ll be gone eventually.’

Another missive she had received read: ‘something big will happen in high school. ’

Madyson Middleton, known to everyone as ‘Maddy,’ was reported missing Sunday night and was found dead in a recycling bin at the apartment complex Monday night.

It has since been revealed that her suspected killer allegedly duct taped, raped, strangled and stabbed the child before throwing her body in the trash.

Charged: Adrian Jerry Gonzalez, 15, left, has been charged as an adult with lying in wait before kidnapping, sexually assaulting and killing 8-year-old Madyson ‘Maddy’ Middleton (right)

'Awkward yo-yoer': Gonzalez, 15, pictured in an image from his now-defunct Instagram page under the user name 'awkwardyoyoer,' was described as a quiet kid known in the neighborhood for his prowess with the toy

Teenage angst: A search of Adrian’s now-defunct Instagram account painted a portrait of a disturbed young man possibly suffering from depression

Gonzalez is facing a half-dozen felony charges, including murder with special circumstances, kidnapping with special circumstances, and four counts of sexual assault.

One of the assault counts mentions use of a deadly weapon as an aggravated circumstance, reported the station KRON4.

A search of Adrian’s now-defunct Instagram account painted a portrait of a disturbed young man, possibly suffering from depression, who may have been harboring suicidal thoughts.

In recent weeks, Gonzalez posted a series of cryptic messages hinting at his inner turmoil, according to reporting by the New York Times.

'Wears all black to try and look powerful and hide the crippling anxiety,' he wrote of himself in one post. 'Towards the future and the constant worry that I’ll never find someone who loves me.'

The last message appeared on the page Monday, the day Maddy was discovered dead. The post included a video showing what appeared to be Gonzalez's fingers on a keyboard playing the song 'Mad World' by the band Tears for Fears.

The clip was accompanied by a post that included lyrics from the song’s refrain: 'The dreams in which I’m dying are the best I ever had.'

Mad World famously appeared on the soundtrack of the 2001 cult classic Donnie Darko, which tells the story of a troubled teenager who is tormented by visions of a giant rabbit that manipulates him into committing a series of crimes.

Since Gonzalez's arrest Monday, more information has emerged about his behavior during the search for Maddy.

Neighbors said the 15-year-old, who was known in the area for his prowess with a yo-yo, showed unusual interest in the case and kept asking searchers about the missing girl.

Dark thoughts: In recent weeks, Gonzalez posted a series of cryptic messages hinting at his inner turmoil. Some of his posts talked about death and his fear of being alone

In custody: Gonzalez was arrested Monday while watching detectives near the bin where Middleton's body was found

Neighbor Setorro Garcia told San Jose Mercury said that Gonzalez seemed obsessed with Maddy's disappearance.

At one point, Garcia recalled that he told the teenager: 'Dude, you're the only one asking me.'

Other residents in the tight-knigt artist's community were taken aback by both the child's brutal murder and Adrian's arrest.

On Wednesday, Santa Cruz County District Attorney Jeffrey Rosell that Gonzalez will be charged as an adult with sexually assaulting and murdering the 8-year-old girl.

Sources say that the shy and somewhat reclusive teenager lured Maddy to his apartment when no one was home, restrained her with duct tape and raped her, after which he allegedly strangled the child and disposed of the body by dumping it in a garbage bin downstairs.

Murdered: Madyson 'Maddy' Middleton vanished from her apartment block in Santa Cruz, California, on Sunday. Her body was found in a nearby recycling bin Monday evening by heartbroken police officers

According to some reports, Maddy Middleton also suffered stab wounds during the attack.

‘Justice demands the charges that we filed,’ Rosell said at a Wednesday morning news conference announcing the charges.

Police said Middleton knew the teen who lured her to his family's apartment at the center, which offers affordable housing to artists, and killed her.

The teen, who acted alone, concealed her body inside a recycling container downstairs, according to police.

Gonzalez was arrested Monday night while watching detectives near the bin where Middleton's body was found, police said. It is believed that Maddy was likely killed before even being reported missing.

‘He's a very, very nice boy,’ 60-year-old Geoffrey Nelson, who lives on the same floor as the teen, told the San Francisco Chronicle newspaper. ‘He is known for being really great with the yo-yo.’

On his Instagram page, which has since been deleted, Gonzalez went by the user name ‘awkwardyoyoer.’

Gonzalez is scheduled to be arraigned Thursday and faces life in prison if convicted.

As Gonzalez was being taken into custody Monday, his mother rushed at police officers in floods of tears, asking why her son was being hauled away in handcuffs.

As the young suspect was taken to a police car, his mother (pictured right) rushed at officers

The distraught mom (second right in white top) demanded to know why her son was being taken away

Santa Cruz Police Chief Kevin Vogel told reporters during a Tuesday press conference that Madyson 'was lured to the suspect's apartment willingly.'

'Additionally, we've determined that Maddy was murdered inside of the suspect's apartment,' he said.

'She was then carried downstairs to the recycle bin, where she was concealed.'

The suspect acted alone 'and not in concert with anyone else.'

Her body was found at 7:55pm Monday.

Vogel added that the girl's body was 'concealed in a way that wasn't obvious or readily apparent.'

Adrian Gonzalez was believed to have helped in the search for Maddy and was arrested around the same time the girl's body was found, according to Vogel.

'It's my belief that she was killed before we got the phone call Sunday night,' Vogel said. The 911 call was placed at 6:08 p.m.

Sea of flowers: Neighbors look at the growing memorial of flowers, stuffed animals and notes left in memory of Madyson Middleton in Santa Cruz Wednesday

The arrest of the boy stunned mourning neighbors who insisted the boy had a good reputation in the community before the horrific act

Terrance Kelly told the San Francisco Chronicle: 'From what I know, he's very well spoken and has a very kind manner. 'It's just a shocking situation altogether.'

The suspect and Middleton were neighbors at the Tannery Arts complex, a public-private nonprofit project that includes 100 affordable loft apartments for artists and their families, a cafe and dance and art studios.

Police had been using scent-specific K-9s from the Office of Emergency Services to hunt for Madyson, who was nicknamed Maddy.

She was last seen alive on surveillance cameras riding her white scooter at around 4pm at the Tannery's courtyard, where children - both residents and those taking art and dance classes - frequently play.

Her mother reported her missing around 6pm after realizing the young girl was gone around 5pm.

Madyson's mother Laura Jordan told KRON4 on Monday afternoon: 'I can't explain how how difficult this is'

She was last seen riding her scooter on video surveillance at 4.12pm on Sunday in (above)

She was last seen riding her scooter in the Tannery Arts Center courtyard and was reported missing at 6pm

Madyson's parents met with investigators Sunday night and again Monday.

During an interview with KRON4, Maddy's mother Laura Jordan, said: 'She was just happy as could be, riding around.'

When asked if her little girl had 'done anything' like this before, Jordan said: 'Nothing. Never. She's never left Tannery property. She knows where she can and can't be here.

'She was in the courtyard where she was supposed to be. And that was the last we saw of her on surveillance.'

When asked how she was coping, Jordan said: 'I already fell apart. Now I'm in survival mode. I can't explain how difficult this is.'

During the extensive search, police did a door-to-door at the complex and visited a homeless resource center and shelter across the street.

Other officers throughout the state used boats, helicopters, motorbikes and dogs to try and find the girl.

The FBI and sheriffs from San Mateo and Santa Clara counties all took part.

Dogs in the search picked up her scent at a beach but the trail went cold

The arts complex, a former leather tannery, is managed by The John Stewart Company.