Witnesses and police described a chaotic scene as a masked attacker armed with two guns shot seven people, killing one, in a Tennessee church before he was subdued.

Burnette Chapel Church of Christ member Minerva Rosa said members were talking about the success of their yard sale the previous day when they heard gunshots outside. The church pastor, David Spann, 60, shouted, “Run, run, gunshots!” as congregants hid under pews or in bathrooms, according to a witness.

A masked gunman carrying two guns entered the church from the back after fatally shooting a woman outside, police said. He then walked through the church silently, shooting six more people before he was subdued by an usher, police said. Police later recovered another pistol and a shotgun from the suspect’s vehicle.

Rosa said the reading that day had been from Luke, chapter 8, and she recalled the part about a woman who touched Jesus and was cured of bleeding. By the end of the shooting, she was on her knees, her dress stained with blood, putting pressure on the gunshot wound in Pastor Spann’s chest. She and others got on their phones to call 911.

Another church member, a 22-year-old usher named Robert Engle, tackled the gunman and suffered injuries when he was pistol whipped. In the struggle, the shooter shot himself, although it wasn’t clear if it was on purpose or an accident. Engle retrieved his own gun from his car and held the man until police arrived, police said.

“He’s amazing,” Rosa told reporters about Engle. “Without him I think it could be worse. He was the hero today.”

Emanuel Kidega Samson. Photograph: Metro Nashville police department/EPA

Authorities identified the attacker as Emanuel Kidega Samson, 25, of Murfreesboro, who came to the US from Sudan in 1996 and is a legal US resident.

No motive was immediately determined. Church members told investigators the suspect had attended services a year or two ago, said Don Aaron, a spokesman for the Metro Nashville police department. Nashville police did not immediately comment on several bizarre posts on the suspect’s Facebook page in the hours before the shooting.

The gunman pulled into the church’s parking lot as services were ending. Melanie Smith, 39, of Smyrna, Tennessee, was killed when the shooter opened fire in the parking lot. Spann’s wife, Peggy, 65, was also shot as well as William and Marlene Jenkins, 83 and 84 respectively, Linda Bush, 68, and Katherine Dickerson, 64. Police said none of the surviving victims suffered life-threatening injuries.

Aaron called Engle “an extraordinarily brave individual”. But in a statement Engle said he did not want to be labeled a hero.

“The real heroes are the police, first responders and medical staff and doctors who have helped me and everyone affected.” Engle asked for prayers for all those injured as well as the shooter.

Blake Langford, 21, got a text from his father telling him not to come to the church where his family attended after the shooting. “My grandmother hid under a church pew. My stepmom and my aunt, they barricaded themselves in the bathroom,” Langford said he learned from his father, who arrived at the church seconds after the shooting ended.

Langford said he knew Engle and believed his actions saved lives. “He’s 6ft 5in, a really big guy, but a gentle giant,” Langford said. “He’s always been that kind of person to put others before himself.”

Forty-two people were at the church at the time of the shooting, Aaron said. The church describes itself on its website as a “friendly, Bible-based group of folks who love the Lord and are interested in spreading his word to those who are lost”. Photos on the church’s Facebook page show a diverse congregation with people of various ages and ethnicities.

On Samson’s Facebook page, a post in the hours before the shooting read: “Everything you’ve ever doubted or made to be believe as false, is real. & vice versa, B.” Another post read: “Become the creator instead of what’s created. Whatever you say, goes.” A third post read: “You are more than what they told us.”

Police charged Samson on Sunday night with one count of murder and said multiple charges were pending. He was ordered held without bond by a judicial commissioner.

After the attack, the nearby New Beautiful Gate Church opened its doors to Burnette Chapel churchgoers as they reunited with loved ones. New Beautiful Gate pastor Michael Mosby said he was neighbors with Spann.

“As a pastor myself, you come with the expectation of sitting down and having a service and not thinking about what can happen around you,” Mosby said. “You never know who is going to come to the door or what reasons they would come to the door, come to your church and do something like that. We’re always on guard. We just thank God many more weren’t hurt.”