Orlando terror attack updates: Obama meets with victims' families in Orlando

Omar Mateen was placed on a terrorist watch list maintained by the FBI when its agents questioned him in 2013 and 2014 about potential ties to terrorism, according to U.S. law enforcement officials who spoke on condition of anonymity to discuss the case.

He was subsequently removed from that database after the FBI closed its two investigations, one official said.

In the first investigation, Mateen was questioned by FBI agents after they were told he had made inflammatory comments that co-workers worried were sympathetic to terrorists.

The FBI agents determined that Mateen had not broken any laws and closed the investigation, a second official said.

They questioned Mateen again the following year because agents had learned he had contact with an American who later died in a suicide bombing in Syria.

Agents closed that investigation because they concluded the contacts with the suicide bomber had been minimal, an FBI official said.

Even if Mateen were still on the terrorist watch list — known as the Terrorist Screening Database — the designation would not have precluded him from buying the semiautomatic pistol and assault-style rifle that he used in Sunday's massacre.

Mateen bought two guns in the last 12 days from a gun store not far from his Florida home, federal officials said.

The Bureau of Alcohol, Tobacco, Firearms and Explosives described the weapons as a “.223 caliber AR type rifle and a 9mm semiautomatic pistol.”