Federal authorities say that the two assault rifles and two handguns used in the San Bernardino massacre were all purchased legally in the United States -- two of them by someone who's now under investigation.
Meredith Davis of the Bureau of Alcohol, Tobacco, Firearms & Explosives says investigators are now working to make a connection to the last legal purchaser.
She says all four guns were bought four years ago but she's not saying whether they were purchased out of state or how and when they got into the hands of the two shooters.
Davis says California requires paperwork when guns change hands privately but many other states don't.
She also says the rifles involved were .223-caliber -- powerful enough to pierce the standard protective vest worn by police officers, and some types of ammo can even plow through walls.
In a Thursday morning media briefing, investigators revealed that the suspects Tashfeen Malik and Syed Rizwan Farook fired dozens of rounds inside the conference room at the Inland Regional Center in San Bernardino. The suspects also had access to 1,600 rounds when they were confronted by law enforcement officers later that day, police said.
The house in Redlands on which police converged and where the suspects’ SUV was initially reported was found to contain 12 pipe bombs, 2,000 9mm rounds, more than 2,500 .223-caliber rounds and “several hundred” 22 long rifle rounds, San Bernardino Police Chief Jarrod Burguan said.
In the state of California, there is no limit law for ammunition on most firearms. There are certain restrictions on types of ammunition. For example, California generally prohibits sale, possession or transportation of any fixed ammunition greater than .60 caliber.
Also, California does not require a license for the sale or purchase of ammunition nor does it keep records for long gun ammunition sales.
There was a law enacted in 2009 requiring the sales of handgun ammunition be recorded.
A 2011 law prohibiting sale of handgun ammunition over the internet or through the mail has been put on hold pending legal appeal.