At least 26 people were killed in a church shooting east of San Antonio, Texas today. Details about the crime, which unfolded at the First Baptist Church of Sutherland Springs at about 11.30am local time, are still emerging, but it has been confirmed that the lone gunman is dead.

Shootings inside a place of worship are typically cast as particularly abhorrent for obvious reasons. These sacred spaces are meant to be sanctuaries for spiritual connection and contemplation. Removed from the pressures of secular society, they are intended to help followers of certain faiths feel physically and psychologically safe. But recent history has seen enough church shootings that the Center for Homicide Research in Minneapolis built a database to track them.

The database only includes Christian churches, not mosques or temples belonging to other faiths, which have also been the targets of numerous attacks in the US. It also only includes church shootings that occurred between 1980 and 2005, and did not keep a tally of any violence that did not involve guns.

Dallas Drake, the principal researcher for the center, told Pacific Standard that the idea to build the database grew out of a discussion about settings where homicides had not occurred. “We were having discussions internally about, ‘Is there any place that hasn’t had mass shootings or mass murders?’ and somebody came up with the idea of perhaps churches,” said Drake. “Of course, we proved that wrong.”

According to the data, which was extracted from newspaper accounts, there was a total of 139 shootings in churches between 1980 and 2005. The total death toll was 185 people, including 36 children. Although hatred of a particular group motivated a significant number of the shooters, in 23 cases, the violence targeted a domestic partner. Ten of the shootings were linked to “religious differences,” and one was called a hate crime.

Were the database maintained over the past 12 years, its statistics would represent some of the country’s most heinous mass murders. For example, it would have shown the nine people killed in the historically black Emanuel African Methodist Episcopal Church in Charleston, South Carolina in 2015. Following that horrific hate crime, the Huffington Post compiled a detailed list of eight church shootings between 2007 and 2014 that totaled 17 deaths.

Most recently in September 2017, a 25-year-old man allegedly shot one woman and injured seven others in Burnette Chapel Church of Christ in Nashville, Tennessee. Speaking to a reporter from The Tennessean after the shooting, the church’s minister Joey Spann said, “Churches, you don’t lock the doors. But we may have to. It’s sad.”