#NYC subway slash suspect kicked out of friend’s pad: ex-pal

One of the accused subway slashers who went on a rampage through the transit system is a former foster child who was crashing at his pal’s Bronx home — until the friend kicked him out, The Post has learned.

Joseph Foster, 18, crashed at friend Jahntonio Grant’s apartment in the Soundview Houses until December, when Grant gave him the boot, he told The Post.

Grant, 23, said Foster has no family in the building and was in the city’s foster care system but had signed himself out. He wanted to help the teen because they both went through the foster care system, Grant said.

“I was introduced to him by someone. I had him staying in my crib for a little bit and started to see red flags,” Grant said.

Grant wouldn’t specify what “red flags” he saw, but noted Foster “wasn’t appreciative of the help he was being given.”

Foster “seemed like an OK person at the time — that’s why I wanted to help him,” Grant said.

“That’s crazy that all that stuff ended up happening,” Grant said of the subway slashings. “He was pretty chill, yeah he had his fair share of issues but who doesn’t?”

Foster was one of four suspects collared Friday in a horrific string of random early-morning subway slashings in Manhattan, police said.

Three of the suspects — including Foster — were awaiting arraignment Saturday in Manhattan Criminal Court.

Another person in custody is not being charged and was cooperative in the investigation, according to sources. The NYPD on Saturday released surveillance video and an image of another wanted suspect.

Grant said he was surprised to learn about Foster’s arrest because he had picked up small side jobs to make money and had a girlfriend.

“If all this time he’s been doing stuff like this then I don’t think there’s no reform….I’m a little disappointed. He’s not someone I would ever extend my help to ever again,” Grant said.

Said Grant: “Given that he went down that road, that bad path, I hope something clicks in him and some sort of change follows.”

Foster now faces one count of robbery and criminal possession of a weapon.

Foster has an open case in The Bronx, according to public records, and was freed without bail in connection with a January arrest for a similar incident, law enforcement sources told The Post.

Additional reporting by Georgett Roberts and Joe Marino.