The Afghan immigrant suspected of planting bombs in Chelsea and New Jersey was a deadbeat dad who raged against gays, the military and American culture, his high school sweetheart revealed on Monday.

“He would speak often of Western culture and how it was different back home,” Maria told FoxNews.com of bombing suspect Ahmad Khan Rahami, the father of her child. “How there weren’t homosexuals in Afghanistan.

“One time, he was watching TV with my daughter and a woman in a [military] uniform came on and he told her, ‘That’s the bad person,’” she recalled.

Maria, who believes Rahami was “brainwashed,” said he brought back a wife and another kid when he came back from a trip to Afghanistan nine years ago.

The 28-year-old terror suspect is a naturalized US citizen whose family was granted asylum in 2011.

Rahami made numerous trips to terror hotbeds Afghanistan and Pakistan in the last 10 years, according to Rep. Peter King (R-NY).

He became noticeably devout after returning from a visit to his homeland two years ago, friends and law enforcement sources said.

“He had changed. He dressed differently, more religiously, the robe and everything,” Flee Jones, 27, a childhood pal of Rahami, told The Post.

“I really never expected it from him. He was always this fun-loving guy, but now he was all quiet. He had found religion. It’s mind-blowing.”

He’s also posted radical Islamic writings on a personal website, sources told DNAInfo.

‘The sister is shocked. She can’t believe what he’s done.’ - Law enforcement source

Despite the red flags, Rahami wasn’t on any terror watch lists before he became the prime suspect in bombings in New York City and Seaside Park, NJ, including one that wounded 29 people when a device exploded in Chelsea, officials said. The New Jersey bombing targeted a military charity run.

He’s also believed to be behind pipe bombs that were found atop a garbage can near a train station in Elizabeth, NJ.

A massive manhunt for Rahami came to a swift end late Monday morning when he was found sleeping in the doorway of Merdie’s Tavern in Linden, NJ.

When cops confronted him, he pulled out a gun and fired multiple times, striking two cops before he was taken down in the shootout.

Rahami was found not far from his home in Elizabeth, NJ, where he worked at his family’s popular restaurant — First American Fried Chicken.

When business was slow, he would often pull out his Koran and play Middle Eastern music, said customer Brayant Ocampo, 17.

“One day I asked him about it and he said it’s like a Bible for our religion,” Ocampo recalled. “He was into his religion.”

Despite going into the family business, Rahami was the “black sheep” of his clan — and didn’t get along well with his dad, his sister told FBI investigators.

“The sister is shocked. She can’t believe what he’s done,” a law enforcement source said.

Rahami’s relationship with his family was so rocky that in 2014, he was arrested on assault charges for allegedly attempting to stab his sister, King said.

She later dropped the charges, but he spent over two months behind bars in Union County Jail, law enforcement sources said.

He also violated a restraining order in 2012 and spent a day in jail, according to sources.

The Rahami family first sought asylum in the US in 1995 when Ahmad was 7 years old — and they opened the fried chicken restaurant in 2002, NBC New reported.

He graduated from Edison High School in 2008 and attended Middlesex Community College, where he was a criminal justice major, between 2010 and 2012, when he dropped out.

The family struggled with money, and in 2005, Ahmad’s father, Mohammad Rahami, filed for bankruptcy, citing $38,609 in debt, records show.

Mohammad claimed on Monday that he had “no idea” about his son’s bomb plots, NBC News reported.

“My heart is very, very…,” he said before trailing off.

His sister, Zobyedh Rahami, posted on Facebook: “I would like people to respect my family’s privacy and let us have our peace after this tragic time.”

Regulars at First American Fried Chicken were shocked by Ahmad Rahami’s arrest, describing him as a friendly guy who would sometimes give out free food to cash-strapped customers.

He also has a fascination with cars — fast ones, several people said.

“All this guy ever talks about is his cars,” said Ryan McCann, 33. “He loves fixing cars up and making them fast. All I ever heard him talk about was Honda Civics, Honda Accords, maybe an Acura. He would soup them up.”

A construction worker who lives next to the fried chicken restaurant described the Rahami family as fiercely private.

“They didn’t really talk to anybody,” said Miguel, 41, who declined to give his last name.

He said Ahmad Rahami and a couple of other restaurant workers stopped talking to him entirely when his Israeli heritage came up during a conversation three years ago.

“The first thing I did after I talked to them is I went to check my car underneath … I went to check for a bomb,” he said.

Former Marine Johnathan Wagner, 26, said Mohammad Rahami once showed him a photo from his days as a mujahedeen fighter in Afghanistan in the ’90s.

“He fought off the Russians,” Wagner said.

“Ahmad as a person never talked about anything personal,” he added. “He would ask, ‘How is your family doing? Do you need some money?’ He seemed normal.”

Additional reporting by Larry Celona and Sophia Rosenbaum