A former friend of Florida school shooter Nikolas Cruz said that the teenager often spoke of murdering people and was frequently abusive in an interview with Good Morning America on Tuesday.

Ariana Lopez, who survived the Marjory Stoneman Douglas High School massacre, by hiding in a closet, said that her relationship with Cruz started out like any other friendship, but soon took a dark turn due to his threatening behavior and love of weapons.

The two eventually grew apart, and that was when he began stalking her and following her and a friend home after school.

Lopez said she reported him to school officials, but it did little to change the situation.

She also said that everyone at the school knew the gunman was Cruz once they heard about the shooting, just one day after the family that took in the young man expressed their shock and disbelief over his actions on the same morning program.

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Opening up: Ariana Lopez spoke with Good Morning America on Tuesday about her former friend, school shooter Nikolas Cruz

Quick conclusion: She said she was not surprised to learn he was the shooter, and would often talk about killing 'our parents, our friends, our boyfriends, our girlfriends' (Cruz in court on Monday left, in a 2016 school fight on right in the white shirt)

"He talked about killing our parents, our friends, boyfriends and girlfriends."



Former friend of Florida school shooting suspect speaks out to @VictorOquendo, saying she and her friends reported him multiple times: https://t.co/ZGimiAMj0m pic.twitter.com/gCCo4iEy4G — Good Morning America (@GMA) February 20, 2018

Lopez made it clear during her interview that Cruz's problematic behavior and mental health issues were on clear display at school.

'He used to sell knives out of his lunch box which I thought was insane. You can't have knives, this is a school', said Lopez of Cruz. 'He would be like, "hey guys, want some knives?".

Cruz was disciplined 25 times by the school before he was expelled in February of last year.

One of the incidents that led to his being disciplined was a fight in September 2016. Footage of the brawl emerged over the weekend.

Cruz was suspended for two days as a result of the fight, which was over a former girlfriend.

An in-home investigation was conducted by Florida Department of Children and Families after the fight and Cruz's late adoptive mother Lynda said it was because the unnamed girl was cheating on her son.

Lynda also said in that report that Cruz did not own a gun and only had an air gun, which had been taken away from him when he did not follow her rules for using the weapon.

She stated that Cruz was only allowed to use the gun in the backyard while aiming at targets, but had broken those rules. The report did not go into any further detail. Lynda died in November 2017

It also revealed that Cruz had posted videos on Snapchat showing him cutting himself.

'Mr. Cruz has fresh cuts on both his arms. Mr. Cruz stated he plans to go out and buy a gun. It is unknown what he is buying the gun for,' the released report said.

Lopez said that the fight at the school was not over a break-up, but rather because Cruz had been physically abusing his girlfriend.

'He would hit her. He would threaten her. He would threaten her family and friends for talking to other guys,' said Lopez.

Cruz's violence was not a surprise by that point, according to Lopez.

'He would talk about how he sympathized with Syrian terrorists and say people who opposed them should be killed. He posted pictures of 15 or more firearms just on his bed. Like this was normal. Like you could even see a hamper in the background,' said the young woman of Cruz's now infamous Instagram posts.

'That's how ordinary this was to him.'

She then added: 'He talked about killing our parents, our friends, boyfriends and girlfriends.'

And while she did not specifically reference Kimberly and James Snead, the couple who took in Cruz after his mother's death, she undermined their claims there was no evidence that he was violent.

'I was thinking about why he could have done this. Because Nik was an avid hunter, I thought about it from a hunter's perspective,' said Lopez of the brutal massacre.

'The freshman building is very difficult to get out of - and when you think about it from the way that a hunter might have, which was the way Nik thought about a lot of things, that was an easy target.'

She then said the same exact thing that almost every single student who attended Marjory Stoneman Douglas High School has stated over the past week in interviews.

'I knew it [was him]. We all did. Everybody who knew him, knew it. Before they announced that he was the shooter - we all knew it was Nik,' said Lopez.

'He was the only person we could think of that would do something like this because it was obvious that he had the power to do this.'

Alerting proper authorities: When they stopped being friends, Lopez said that Cruz would stalk her and follow her and a friend, incidents she reported to school officials

Shock and surprise: Lopez's interview came one day after the couple who took Cruz in, Kimberly and James Snead (above), said he was a polite and well mannered boy

The Sneads say the teen being described by former friends is different to the boy they knew at home.

James Snead told ABC: 'He was very polite, he seemed normal. We knew he had one Instagram account. ... The other ones he had, we had no idea about.'

His wife told the Sun Sentinel: 'We had this monster living under our roof and we didn't know,'

Cruz is facing 17 counts of premeditated murder after the attack on Wednesday. It is the deadliest shooting ever at a U.S. high school.

The Federal Bureau of Investigation has acknowledged it failed to act on a tip called in last month warning that Cruz possessed a gun and the desire to kill.