Federal prosecutors are seeking to block the family of San Bernardino shooter Syed Rizwan Farook from receiving more than $250,000 in life insurance payments from his death. The government filed a civil forfeiture action Tuesday to seize the proceeds of two life insurance policies held by the 28-year-old.

The government has alleged that the proceeds from Farook’s policies were derived from a terrorist act. Farook and his wife, Tashfeen Malik, opened fire at a holiday party at the Inland Regional Center in California, killing 14 people and injuring 22 others on Dec. 2, 2015. Investigators believe that the couple was inspired by Islamic extremism.

“Terrorists must not be permitted to provide for their designated beneficiaries through their crimes,” U.S. Attorney Eileen Decker said in a statement. “My office intends to explore every legal option available to us to ensure these funds are made available to the victims of this horrific crime. We will continue to use every tool available to seek justice on behalf of the victims of the San Bernardino terrorist attacks.”

According to prosecutors, Farook obtained two life insurance policies from Minnesota Life Insurance Group through his job with San Bernardino County — one in 2012 for $25,000 and another in 2013 for $250,000. For both policies, Farook reportedly listed his mother, Rafia Farook, as the beneficiary.

The FBI, which is investigating the December incident as an act of terrorism, is still working to determine the motive behind the attack. Farook and Malik had pledged allegiance to a leader of the Islamic State group on Facebook hours before the shooting, but authorities have found no evidence that the couple was directly linked to any overseas terrorist group or received any outside support.

In March, the U.S. Department of Justice unlocked the iPhone used by Farook with the help of an unidentified third party after Apple refused to bypass the device's encryption features.