AP FACT CHECK: Assessing Trump's take on Ohio State attacker
When the family arrived in the U.S., Artan had a secondary inspection by immigration officials, but no negative information was found and he was allowed into the country, according to a U.S. official briefed on the case.
The government conducted a second background check on Artan when he became a legal permanent resident in 2015.
If Trump was referring to his proposal to end some refugee processing and to block migration from certain countries, that's a different issue.
During the presidential campaign, Trump initially proposed banning all Muslims "entering the United States until our country's representatives can figure out what is going on."
Trump will have authority to control the volume of refugees entering the country, but may need legislative and likely diplomatic support to bar migration from certain countries.