HOUSTON (CBSDFW.COM/AP) — There had been a suggestion that a second person involved in a shooting at a Texas naval air base was on the loose, but Tuesday the FBI said its investigation points to only one attacker.

FBI Supervisory Senior Resident Agent Leah Greeves said last week that investigators were working to determine whether a second person of interest was at large following the shooting at Naval Air Station Corpus Christi. The Thursday attack left a sailor wounded and the gunman dead.

But the agency’s Houston office said on Twitter Tuesday that “while there was initial concern about a potential second person of interest, intense investigation leads us now to believe there was not.”

The FBI also repeated that the shooting is being investigated as a “terror-related incident,” without elaborating on what that means. Two officials familiar with the investigation previously told the Associated Press that agents were examining social media posts they believe the shooter made expressing support for extremist groups, including Al-Qaida in the Arabian Peninsula.

Officials have identified the gunman as 20-year-old Adam Salim Alsahli, a Corpus Christi resident who had been a student at a local community college. Security officers shot and killed him after he opened fire while trying to drive a truck through a base entry gate.

The FBI said Tuesday that Alsahli was a Syria-born American citizen. An agency spokesperson did not immediately respond to a request for comment.

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)