Ahead of a Thursday afternoon news conference in West, the Dallas Morning News reported Thursday that State Fire Marshal and ATF officials investigating the cause of the April 17 explosion of the West Fertilizer Plant have found 3 possible causes.

The 3 likely causes cited in the report are an electrical problem in the building where the initial fire ignited, a spark from a golf cart used at the plant and the possibility of a criminal act.

The problem with the first two theories, a source told the Dallas News, is that the explosion seems to have destroyed any evidence that could have decisively proven anything. A Dallas News editorial cited reports from the U.S. Consumer Product Safety Commission concerning the recall of several golf cart models that may have been used in the plant, but investigators say the explosion destroyed the cart in question and they cannot determine what model it was. Any evidence of an electrical problem was also destroyed, they said.

That leaves the possibility of arson, but investigators are ruling the cause “undetermined” today.