A man dressed in black tactical-style gear and armed with an assault rifle opened fire inside a church in a small South Texas community on Sunday, killing 26 people and wounding about 20 others in what the governor called the deadliest mass shooting in the state's history. Officials didn't identify the attacker during a news conference Sunday night, but two other officials â€" one a U.S. official and one in law enforcement â€" who were briefed on the investigation identified him as Devin Kelley. They spoke to The Associated Press on the condition of anonymity because they weren't authorized to discuss the investigation. The U.S. official said Kelley lived in a San Antonio suburb and doesn't appear to be linked to organized terrorist groups. The official said investigators are looking at social media posts Kelley may have made in the days before Sunday's attack, including one that appeared to show an AR-15 semiautomatic weapon. At the news conference, Freeman Martin, the regional director of the Texas Department of Public Safety, said the attacker was dressed all in black, wearing tactical gear and a ballistic vest, when he arrived at a gas station across from the First Baptist Church at around 11:20 a.m. He crossed the street and started firing a Ruger AR rifle at the church, and continued after entering the building. As he left, he was confronted by an armed resident who chased him. A short time later, the suspect was found dead in his vehicle at the county line, Martin said. There were several weapons inside. Martin said it's unclear if the attacker died of a self-inflected wound or if he was shot by the resident who confronted him. He said investigators weren't ready to discuss a possible motive for the attack. He said the dead ranged in age from 5 to 72 years old. Twenty-three were found dead in the church, two were found outside and one died after being taken to a hospital. Federal law enforcement swarmed the small community 30 miles southeast of San Antonio after the attack to offer assistance, including ATF investigators and members of the FBI's evidence collection team.