A maniac who slashed three elderly straphangers at Grand Central Terminal before he was shot dead by cops only kept his machete as protection, his friend claimed.

Family friend Deborah Brown refused to believe deranged attacker Anthony Griffin could have committed the crime — even though she admitted he suffered from mental health issues and carried a machete around with him, she said.

“If he did do that – they’re saying he did this – I wanna see proof of it,” Brown, the mother of Anthony Griffin’s long-time partner, told News12 in an interview broadcast Sunday.

The NYPD said that Griffin was shot and killed by cops after he attacked three people on an uptown 4, 5, 6 subway platform around 9:50 a.m. Saturday morning and refused to comply with orders to drop his machete.

Griffin’s attack left deep cuts to an 85-year-old man and a 65-year-old man, cops said. He also slashed slashing a 70-year-old woman’s shoulder, police said.

Brown said she first heard from her daughter that Griffin had been involved in the attack and shot. Griffin was a rapper who used the name “Fox 5,” neighbors told The Post.

“My daughter called me. She was emotional. She was crying. ‘Mom! Mom! They killed Fox, mom!’” Brown told News12

Griffin’s attack on the subway is out of character for him and he would never hurt anyone, according to Brown, who wished cops would have used a stun gun on him instead.

“You could have Tased him, made him drop the weapon. You don’t have to shoot and kill him,” Brown said.

But she also admitted that Griffin kept a machete on him for protection and had recently been through a rough patch of mental issues.

“I wanna also say that maybe something did trigger, but still it ain’t right,” Brown said.