Internal investigators have concluded that a Dallas police gang unit supervisor failed to follow standard operating procedures on the night that one of his officers was fatally shot earlier this year.

Sgt. Juan Salas, 33, is expected to receive a written reprimand and is to be transferred out of the unit on Wednesday.

"His chain of command believes it is in his best interest and that of the gang unit to reassign him," said Lt. Andrew Harvey, a police spokesman.

Salas is out of town and could not be reached for comment.

Senior Cpl. Norman Smith, 43, was fatally shot Jan. 6 as he and other uniformed gang unit officers attempted to serve a felony warrant at an east Oak Cliff drug den.

The unit's procedures require that supervisors check with other agencies to make sure that their operation doesn't conflict with that of another law enforcement entity in a process is known as "deconfliction."

Supervisors also are required to notify a patrol station that they are going to be in their division and inform the communications division of their whereabouts.

Salas, who was assigned to the gang unit in 2006, did none of those things, an internal investigation found.

Authorities say that even if Salas had followed proper procedures, they do not believe the outcome of the shooting would have been any different. Smith suffered massive trauma from the bullet that struck his face.

Earlier that evening, Smith had received information about the whereabouts of a wanted felon whom authorities had been trying to catch. He and other gang unit officers had just finished a 12-hour shift when they decided to go to the apartment where the fugitive was believed to be holed up.

Smith, flanked by two other gang detectives, knocked on the door.

Smith's positioning – his body in front of where the door was cracked open as he tried to prevent Charles Patrick Payne from shutting it – put him in a more vulnerable position. A shot rang out, striking Smith in the face.

Gang unit officers then pulled their fallen comrade out of the line of fire.

The internal investigation also found that Salas failed to order his officers to set their handheld radios to the same channel, causing confusion in the moments just after the shooting.

The first gang unit officer to call for help had a handheld radio set to the northeast patrol's regular traffic channel. Hearing that an officer was down and thinking it was in the northeast division, police dispatchers conducted a roll call of officers in that division to try to figure out who was injured.

The failure of Salas to notify the patrol station or the communications division of his officers' location, combined with the garbled frantic calls for help from gang unit officers, caused those responding to the "officer down" call to briefly not know where to go, the investigation found.

The Smith shooting also led officials to realize that an almost casual approach had taken hold in a department that serves thousands of felony arrest warrants, prompting an intensive review of the department's arrest warrant procedures.

That spurred officials earlier this year to sharply limit the number of officers who can serve arrest warrants on suspects considered dangerous. The department also instituted special, recurring training, along with rules that limited the serving of felony warrants to specialized squads.

Payne has been indicted on one count of capital murder of a police officer and two counts of attempted murder of a police officer.