Trying to solve the mystery of Tashfeen Malik, a Pakistani mother of a six-month-old baby, who donned the mantle of a shooter along with her husband, US officials are now seeking cooperation from Pakistani officials on the background of the woman, a media report said.
Malik, 27, and Chicago-born Syed Rizwan Farook, 28, whose parents migrated to the US from Pakistan are the shooter couple said to be behind the ruthless killing of 14 people and injuring 17 others in a mass shooting in San Bernardino, California on Wednesday.
The couple was shot dead by police hours later near their apartment in a firefight.
According to NBC News, Pakistani authorities are working with US officials to uncover details of Malik and her family.
Malik came to the US on a K-1 visa as Farook's fiancee.
She later received permanent residency and still had a Pakistani passport in her possession. She married Farook in Saudi Arabia two years ago.
"Pakistani authorities are in touch with Homeland Security in a bid to trace details about the woman," NBC News reported in a news dispatch from Islamabad.
In another report, CNN quoted law enforcement authorities as saying that Tashfeen helped radicalise her husband Farooq and using a different name, she pledged allegiance to Islamic State (IS) leader Abu Bakr al-Baghdadi in a Facebook post.
"This is looking more and more like self-radicalisation," a law enforcement official said.
However, David S Chesley, a lawyer for Farook's family refuted these allegations and said the numbers do not add up.
"It just doesn't make sense for these two to be able to act like some kind of Bonnie and Clyde or something. It's just ridiculous. It doesn't add up," he told CNN.
Yesterday, President Barack Obama cautioned against jumping to conclusions till the FBI investigation is over.
Law enforcement agencies, including the FBI which has a lead in investigations, are struggling to determine the motive behind the Pakistani-origin couple responsible for the deadliest shooting in recent years, leaving a six month-old baby behind.
Investigators are trying to determine whether explosives left at the scene of the mass shooting in San Bernardino were based on a design found in an online publication of al-Qaeda in the Arabian Peninsula, the Los Angeles Times reported.
Sources, who spoke on condition of anonymity, noted that the design is easily accessible and doesn't mean the attack was related to al-Qaeda.
The police found a huge haul of ammunition left behind in the couple's apartment.
Initial investigations have indicated that Farook was in contact with a small number of suspected extremists - one linked to al-Shabaab and another to Jabhat al-Nusra, al- Qaeda's Syrian affiliate - who were the subject of FBI terrorism investigations.
Though the inquiries were ultimately dropped and no charges were filed. However, US officials have cautioned against arriving at a conclusion.
"We do not yet know the motive; we cannot rule anything out at this point," David Bowdich, the Assistant Director of the FBI's Los Angeles office, told reporters.
