SUTHERLAND SPRINGS, TX — About half of the victims killed in the worst mass shooting inside a house of worship in American history were children, a Texas sheriff said Monday.

About two dozen people were shot dead during the Sunday massacre at First Baptist Church in Sutherland Springs, a small, tight-knit town about 30 miles outside of San Antonio. Of them, 12 to 14 were kids, according to Wilson County Sheriff Joe Tackitt.

In addition to the dead, at least 19 people were injured, according to three area hospitals. The ages of the injured was not yet known.

Authorities have said the ages of the victims range from 5 to 72, although one family says an infant girl was also among those killed.

The identities of the victims have not yet been confirmed. According to The Washington Post, Joe and Claryce Holcombe lost eight members of their family, including children, grandchildren and great-grandchildren.

The suspect, Devin Patrick Kelley, 26, of neighboring Comal County, began firing outside the church at around 11:20 a.m. local time with an assault-type rifle, and then continued shooting inside, officials said. He died of a gunshot wound after a local resident confronted him and pursued him in his car, they added. It wasn't clear whether he died of a self-inflicted shot or of a gunshot fired by the resident, Johnnie Langendorff.

Tackitt said on Megyn Kelly TODAY that the suspect's in-laws attended the church, although they weren't there at the time. The in-laws were speaking with investigators, Tackitt said.

This is a developing story, please check back for updates.