(Reuters) – Federal authorities said they have arrested a Florida truck driver who “was thinking about shooting up a church” in Memphis this week, making him at least the fourth person this month charged with plotting a mass shooting.

The Federal Bureau of Investigation arrested Thomas McVicker, 38, in Indianapolis on Monday after a friend in Alabama alerted agents to text messages he sent in which he described his plans for a mass shooting and suicide, according to court papers.

McVicker, who is from Punta Gorda but lives in his truck, is under treatment and is on medication for schizophrenia, according to his mother, FBI Special Agent Ketrick Kelley said in an affidavit filed in U.S. District Court in Alabama.

It was not immediately clear if McVicker had an attorney.

The alleged mass shooting, which Kelley said McVicker appeared to be planning to carry out on Thursday, comes after law enforcement authorities in Ohio, Florida and Connecticut said they arrested three men who planned mass shootings.

Since July 28, shooting sprees in Gilroy, California, El Paso, Texas, and Dayton, Ohio, killed 34 people.

(Reporting by Peter Szekely in New York; Editing by David Gregorio)