KILLEEN, Tex. — The Army specialist at Fort Hood who killed three and wounded 16 of his fellow soldiers on Wednesday had an angry dispute over a leave request shortly before the shooting rampage, a law enforcement official said Friday.

After a meeting where he had sought a leave to attend to family matters, he was clearly agitated and disrespectful when his request was denied, said the official, who asked not to be identified because he was not authorized to discuss the investigation.

Fort Hood officials and a spokesman for Army investigators declined to comment on Friday about the meeting and its role in the shooting, but they confirmed in an afternoon news conference that the specialist, Ivan Lopez, became angry with soldiers from his unit before the attack. Two of those he killed were in his unit, a transportation battalion of the 13th Sustainment Command. Officials stressed that they had still not established a clear motive.