UPDATE III: Gunman fought government over social security payments

"Johnny Lee Wicks, identified as the man who opened fire at the federal courthouse Monday morning in downtown Las Vegas, has been at odds with the federal government over Social Security benefits for about two years," Steve Green reports for the Las Vegas Sun.

He "likely was surprised and upset to learn that his Social Security benefits would be reduced due to the move because he would be losing a 'California State Supplement’' of $317 a month to his federal Social Security benefits."

Wicks filed a "lawsuit alleging that in cutting his benefits, his civil rights were violated by the agency because of his race (black)."

The LA Times notes, "Law enforcement sources said Wicks' failed federal lawsuit -- an erratic document riddled with spelling and grammatical errors -- was a likely motive.."

WATCH: Cellphone video footage of shootout at federal courthouse in Las Vegas -- video follows below

UPDATE II: One of the two federal agents injured in a shootout outside a federal building in Las Vegas has died, hospital officials confirmed to the Las Vegas Review-Journal.

The deceased man has so far only been identified as a court officer. According to CNN, the other federal agent was a deputy with the US Marshals office. His condition is unknown at present.

The suspected lone shooter, still unidentified at this time, was earlier confirmed to have died after sustaining injuries in the gunfight. CNN has obtained cellphone footage of the shootout. At least 36 gunshots can be heard in the video.

Download video via RawReplay.com

The Review-Journal offers a vivid moment-by-moment eyewitness description of the shootout, which took place at the Lloyd D. George Federal Courthouse, which also houses the offices of Nevada Sens. Harry Reid and John Ensign.

Mario Senu, a defense attorney, said that about 8 a.m. he was walking on the sidewalk next to the courthouse heading toward the entrance when he heard a "pop." He said he thought it might be a gun but didn't think it was near him because of the way sounds reverberate off the building, so he kept walking.

Five seconds later he heard "five pops" in succession, he said. He said when he turned the corner he saw a man who didn't appear to be a police officer in an "attack stance" aiming "a long gun" at the entrance of the building. This shooter was hiding behind a column. Then he saw another man with what appeared to be a long gun.

As Senu ran away, he said the barrage intensified, possibly as marshals returned fire from the courthouse.

"I go to gun ranges and don't hear that much ammo," Senu said.

UPDATE: Multiple news sources confirm that that a suspected gunman involved in a shooting at a federal building in Las Vegas has been killed.

Two federal employees -- one an agent of the US Marshal service, the other a courthouse security officer -- were shot in the altercation Monday morning. While some news sources have reported that the two were killed, officials continue to say that their condition is unknown at the present time.

The shootout took place at the Lloyd D. George Federal Courthouse in Las Vegas, around 8 a.m. local time Monday. CNN reports that the building houses the offices of Nevada congressmen Harry Reid, the Senate Majority Leader, and John Ensign, the scandal-plagued Republican senator. Neither of the two lawmakers were reportedly in the building at the time.

Original story follows below

Two federal agents are among the casualties in a shootout at the federal building in Las Vegas, Nevada, according to breaking news reports.

Special Agent Joseph Dickey told media that a suspected shooter in the incident has been shot and killed. Conflicting news reports suggest the two federal agents may also have been killed.

The Las Vegas Review-Journal initially reported that police confirmed to the newspaper that two FBI agents were shot, and a third person, who may have been the shooter, has been taken into custody.

But the Associated Press reports the two individuals may have been federal marshals. Las Vegas radio station KDWN is reporting that the shooting may have begun outside the building, and moved into the lobby.

The conditions of the two federal agents and the shooter were not known, the Review-Journal reported, but MSNBC is reporting that both agents were killed. The network says authorities may be looking for another shooter who may be at large.

The news network identified one of the victims as Special Agent John Bailey. Fox News reports that the federal agents may have been federal protective service officers, rather than US marshals.

This story will be updated as details become available...

This video is from CNN's Newsroom, broadcast Jan. 4, 2010.

Download video via RawReplay.com