A man charged in a mass shooting at a Tennessee church expressed suicidal thoughts in June and had a volatile relationship with a woman that twice involved law enforcement this year, according to police records.

Emanuel Kidega Samson, 25, is charged with the fatal shooting of one woman and is expected to face several more charges following the rampage that left six others wounded on Sunday.

Samson wore a tactical vest and fired 12 rounds from a .40-caliber handgun, reloading it once, Nashville police spokesman Don Aaron said. He was also carrying a loaded 9 mm handgun and had a .22-caliber pistol and military-style AR-15 rifle in the car he had left running outside the church, police said.

Police did not find any AR-15 ammunition on the scene, Aaron said.

According to an affidavit, Samson told Nashville police after his arrest that he arrived at the church armed and fired upon the building.

Court documents do not indicate whether Samson has an attorney. His first court hearing is Wednesday.

Police in Murfreesboro, about 20 miles (32 kilometers) southeast of the church, responded to a call from Samson's father, who had reported that his son had texted him June 27 to say: "Your phone is off, I have a gun to my head, have a nice f------ life."

Samson's phone was traced to a Nashville business and officers checked on Samson's welfare. They described his demeanor as "professional" and said they had "no reason to believe" that he would harm himself, Aaron said.

In January, Murfreesboro officers responded to two domestic disturbances between Emanuel Samson and a woman who accused him of cheating on her. Samson cut his hand when he punched a small TV on her desk, according to statements to police.

In March, police were dispatched to Samson's home, where he said the woman was trying force entry despite his attempts to break off contact with her. He told officers he was afraid of her because she had struck him in the past.

No charges were filed in either incident.

On Sunday, toward the end of services at the Burnette Chapel Church of Christ, Minerva Rosa said church members were talking about the success of their yard sale the previous day when they heard gunshots outside the building. The church pastor, David Spann, 60, then shouted for everyone to run, according to a witness.

The gunman 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 Robert Engle, a 22-year-old usher, tackled him.

In the struggle, the gunman 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.

Authorities said Samson came to the United States from Sudan as a child in 1996 and is a U.S. citizen.

No motive had been determined by Monday evening. Church members told investigators that Samson had attended services a year or two ago.

Melanie Smith, 39, of Smyrna, Tennessee, was killed in the parking lot. Spann's wife, Peggy, 65, was 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.

Forty-two people were at the church at the time, Aaron said.

In 2014, Samson obtained a license to work as an unarmed security guard, according to state Department of Commerce and Insurance records. The following year, he worked for nine days for the state Department of Mental Health and Substance Abuse Services, but spokesman Matthew Parriott declined to say what his job was.

Samson's security guard license expired in 2016, but Samson enrolled in a course to renew it on Friday — two days before the shooting.

Samson registered for a training course with Academy of Personal Protection and Security and initialed language stating that he was "presently in good physical and mental health."

Company owner Buford Tune told WTVF-TV that Samson didn't stand out much during the course beyond scolding another attendee for not paying attention. The course does not cover physical or defense tactics, Tune said.

Samson went to work on Saturday with Crimson Security, Aaron said, but sent an email to a company official on Sunday at 10:01 a.m. saying he appreciated the opportunity but would not be returning.

Childhood friends on Facebook remembered Samson as a skinny kid in middle school, a stark contrast to the imposing body builder he developed into.

Samson took his workouts seriously, posting several images of himself flexing his muscles on social media. In November, he entered into the novice class of the Music City Muscle competition and came in seventh in the men's physique category.

Neighbor Dejuan Martin told WSMV-TV that he has known Samson for about five years, and once attended Bible study with him. He described him as goofy and passionate.

"I would never say that he was like a bad person, I just couldn't say that," Martin said. "He never showed any bad tendencies."