Parkland school shooter Nikolas Cruz's mother was an 'enabler' who 'didn't care' if her son had a gun, even though experts said he shouldn't.

The 19-year-old legally bought the AR-15 assault rifle he allegedly used to gun down 17 kids at Stoneman Douglas High School on Valentine's Day.

Numerous counselors tried to help the troubled teen, who had a developmental age of three and behavioral and emotional issues since middle school.

Parkland school shooter Nikolas Cruz's mother was an 'enabler' who 'didn't care' if her son had a gun, even though experts said he shouldn't, a hearing heard

But they were blocked at every turn by his mother Lynda Cruz, who died of pneumonia three months before the massacre.

'His mother was an enabler, and his mother contributed to this significantly,' Pinellas County Sheriff Bob Gualtieri told a committee investigating the shooting.

'To the point where at one time when they said that he wanted to buy a gun and the counselors from the school said he shouldn't have a gun, his mother said, 'I don't care. If he wants a gun, he can have a gun.'

Sheriff Gualtieri, who leads the committee, said mental health and school counselors contacted Ms Cruz about 140 times but she often interfered.

'This is not a situation where there wasn't yeoman's work being done by a whole bunch of people to try and get this guy off the path that he was on,' he said.

'But it just wasn't being effective.'

'His mother was an enabler, and his mother contributed to this significantly,' Pinellas County Sheriff Bob Gualtieri told a committee investigating the shooting

The 19-year-old legally bought the AR-15 assault rifle he allegedly used to gun down 17 kids at Stoneman Douglas High School on Valentine's Day

An investigator from the Florida Department of Children and Families visited Cruz on September 28, 2016, after he posted a video to Snapchat of him cutting himself.

He wrote n****r and a Nazi symbol on his book bag, which his mother made him rub off, and was on medication for depression, the investigator reported.

Cruz also told his mother he planned to buy a gun, but she didn't know why.

Sheriff Gualtieri also insisted the Promise program Cruz was sent to after he smashed a sink in the boy's bathroom at school had no link to the shooting.

He said the program didn't 'fail' Cruz and even if he didn't attend the three-day diversion it wouldn't have stopped him buying the gun.

'It would never in any way, shape, form, would've affected his ability to buy that AR-15, to buy the shotguns, to buy anything else, to possess them,' he said.

'It's completely irrelevant, it's a rabbit hole, it's a red herring, it's immaterial, and that's why we're taking it off the table.'

Numerous counselors tried to help the troubled teen, who had a developmental age of three and behavioral and emotional issues since middle school

Sheriff Gualtieri said even if Cruz was charged with a misdemeanor for the damage, the maximum penalty would have been community service.

'Even if you assume that he should've received the maximum of everything, it is irrelevant, it's immaterial to what happened on Feb. 14, and it wouldn't have changed the outcome one bit,' he said.

'Quite frankly I don't think this event in and of itself, breaking a handle on a faucet, had anything to do at all with the mass shooting.'

The commission will on Thursday discuss his mental health treatment in a closed session as his medical records are legally protected.

Broward school district lawyers are also trying to publicly release a report that includes Cruz's official school records, but the teen's lawyers are arguing to block it.