The female jihadist who helped her husband slaughter 14 people in the San Bernardino rampage pledged allegiance to ISIS on Facebook during the massacre — and is believed to have radicalized her spouse, sources said Friday.

Tashfeen Malik, 27, vowed her support for the terror group’s leader, Abu Bakr al-Baghdadi, on the site at around 11 a.m. Wednesday just as the first 911 calls were made by workers at the attacked Southern California facility.

The message, later scrubbed by Facebook for violating its code of conduct, was posted under a different name.

“Investigators believe this is ISIS-inspired. She pledged her allegiance to al-Baghdadi,” a source briefed on the matter told The Post.

David Bowdich, assistant director of the FBI’s Los Angeles office, said authorities were “aware” of the post and looking into the “pledge of allegiance.”

Pakistani intelligence officials were also probing Malik’s ties to Muslim cleric Maulana Abdul Aziz, who led al Qaeda militants in a bloody siege in 2007 at Pakistan’s Red Mosque, which has been a base for extremists.

The two were seen together in Islamabad, where Aziz is still a prayer leader at the mosque — and, according to The Telegraph, possibly building a militia.

And investigators believe Malik and/or her husband, Syed Rizwan Farook, met with al Qaeda terror suspects while in Saudi Arabia, Fox News reported.

Authorities are also investigating the “very serious” possibility that Malik was the one who radicalized Farook before they launched their attack on his co-workers at the Inwood Regional Center, Fox News reported.

The husband and wife were killed shortly after the attack in a shootout with police.

The developments came as reporters flooded the couple’s Redlands home Friday, revealing a trove of items — from mundane objects like baby toys to shredded documents and credit cards.

Journalists combed through the townhouse after being let in by the landlord, and the chaotic scene was broadcast on live TV.

Among the items strewn on a bed were photo ID cards, driver’s licenses, bank statements, business cards and a Social Security card belonging to Rafia Farook, Syed’s mother. Names and numbers were clearly visible.

The FBI had cleared the home a day earlier.

The FBI search revealed the couple had been stockpiling thousands of rounds of ammunition and building explosives in a bomb lab.

They had even planned to use miniature Christmas-tree lights with green insulated wire to set off explosives, according to documents obtained by NBC News.

Law-enforcement sources told Fox News that there’s a “very strong” possibility that Malik may have been Farook’s terror trainer, helping him build those bombs.

Malik, 27, was born in the Punjab province of Pakistan but moved to Saudi Arabia with her family 25 years ago.

Her father’s views became more militant after the move, a family member told Reuters.

“When relatives visited him, they would come back and tell us how conservative and hard-line he had become,” said Malik’s uncle Javed Rabbani.

Two Pakistani officials told Reuters that she had gone home five or six years ago to attend Bahauddin Zakariya University in Multan and study to become a pharmacist.

In 2014, she traveled with Farook to the terror hotbed to secure a K-1 “fiancée” visa, according to a Pakistani source familiar with the matter.

They then traveled back to Saudi Arabia before entering the United States in July.

One of Farook’s co-workers, Christian Nwadike, said his colleague was never the same after coming back from Saudi Arabia with his new bride.

Asked whether he believed Farook had been radicalized, Nwadike replied: “Yes, by the wife. I think he married a terrorist.”

“He was set up through that marriage,” he added.

FBI Director James Comey said Friday that the attack, which also left 21 wounded, was being investigated as a terrorist act.

“And the reason for that is the investigation so far has developed indications of radicalization by the killers and of potential inspiration by foreign terrorist organizations,” he said.

He added that, so far, there’s “no indication that these killers are part of an organized larger group or a part of a cell.”

But they are looking into “telephonic communications” one of them made with someone the FBI is investigating, said Bowdich, of the FBI’s Los Angeles office.

While no other arrests have been made, authorities do know who bought two semiautomatic assault rifles they used during the terror rampage, Bowdich said.

Comey demurred when asked whether Malik radicalized her husband.

“Being a husband myself, we’re all influenced to an extent” by our wives, he said.

The glimpse inside of the couple’s townhouse revealed the domestic side of their life.

Found belongings included a children’s activity book called “Islamic Manners.”

Also inside were numerous Islam-related articles, from a prayer rug to a Muslim community center sticker.

Landlord Doyle Miller, who let the reporters inside, said he had no idea his tenants would become murderers.

“They didn’t say they were terrorists when they moved in,” Miller said.

Additional reporting by Natalie Musumeci