Nearly two weeks after the terror attack in San Bernardino, investigators have not announced any arrests as the investigation into the killers drags on.

An underwater search for a computer hard drive and anything else linked to the husband-and-wife shooters concluded on Saturday. FBI spokeswoman Laura Eimiller said specialized divers with the agency concluded their search through a San Bernardino lake for abandoned evidence. However, she declined to say whether any items recovered are related to the probe.

The search began Thursday after authorities learned the shooters, Syed Rizwan Farook, 28, and Tashfeen Malik, 29, may have been in the area the day of the attack, said David Bowdich, chief of the FBI's Los Angeles office. Investigators were tipped that the small lake in a park about 3 miles from where the shootings happened might hold the hard drive, according to a law enforcement official briefed on the investigation but not authorized to speak publicly about the case.

Farook, a U.S. citizen, and his Pakistani-born wife, opened fire Dec. 2 at a holiday luncheon attended by many of Farook's co-workers in the San Bernardino health department, killing 14 people. The couple died in a shootout with law enforcement hours later, leaving behind a 6-month-old daughter.

Farook's longtime friend and relative-through-marriage, Enrique Marquez, bought the assault rifles used in the shooting more than three years ago, about the time he converted to Islam, according to the law enforcement official. Farook asked Marquez to buy the rifles because he was worried he wouldn't pass the background check himself.

Marquez, who checked himself into a mental hospital after the attack, told investigators that he and Farook were plotting an attack in 2012.

Investigators have said the killers tried to cover their tracks by destroying emails, cellphones and other items at their home in Redlands.

The Associated Press contributed to this report.