A Texas man is accused of booby-trapping public toilets with pressure-activated explosives, which injured three people.

The first attack was reported July 20 at the Wash Tub car wash in Helotes, which is about a half hour northwest of San Antonio.

Employees reportedly were able to identify Alden to police because he was a 'regular customer' who used a membership card.

A woman allegedly sat down on the toilet at the car wash after which a small explosion occurred.

Detectives said a woman was injured but left the location before the police report was made, KENS-TV reported.

"The female customer was reportedly very upset and left the location before a report was made," the affidavit states. "The Helotes Police Department responded to the location to take the report and document the scene."

Investigators discovered "small, readily available commercial fireworks that are designed to explode when pressure is applied," according to the outlet.

Six days later, two more people were injured from booby-trapped toilets at a Wash Tub in San Antonio.

A female employee and a young girl were victims of the explosives within minutes of each other, according to the affidavit.

Investigators reportedly found remains of the small fireworks in the two bathrooms.

Citing a probable cause affidavit, Law & Crime reported that a Wash Tub representative said that on both dates "loud bangs were heard in the bathroom by customers using the bathroom/toilet.”

In all three cases, a man was caught on security cameras entering and leaving the unisex bathrooms, sitting in the lobbies of the car washes, watching the bathroom door, and then leaving after the explosives went off, the affidavit read.

On Aug. 1, police arrested 46-year-old Paul Moses Alden of Helotes.

Alden was charged with arson causing reckless damage or bodily injury, according to police records.

His bond was set at $50,000, and he was bailed out the same day he was arrested.

Court records show Alden is awaiting indictment. A court date has not been set for his next hearing.

Employees reportedly were able to identify Alden to police because he was a "regular customer" who used a membership card. Police reportedly had video of Alden as well as his vehicle and license plate.

A Wash Tub spokesman said, "We are very pleased with the quick action of the San Antonio Police Department and the arson investigator working this case. We will continue to fully cooperate with SAPD and the district attorney's office."

Both fire and police departments are still investigating the exploding toilets.

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