BEAUMONT, Texas -- In southeast Texas, federal agents are investigating the bombing of an Episcopal church in the city of Beaumont. No one was hurt, but there are concerns it could possibly be the work of a serial bomber.

The Thursday morning blast at St. Stephen's Episcopal Church caused minimal damage, but prompted a big response, with the Bureau of Alcohol, Tobacco and Firearms (ATF) and Federal Bureau of Investigation (FBI) assisting the Beaumont Police.

Amanda Pena and her newborn daughter were asleep in a house across the street when it happened.

"I heard the loud noise, and my husband heard it at the same time, and he just jumped out of bed," she said. "To me, cause I saw a dim light, I thought it was just like lightning and thunder."

Two weeks ago, a Starbucks employee found an explosive device at the coffee shop, less than two miles away. Law enforcement sources say it was a working bomb, and that there was a note that said "die USA," and referenced the city of Austin.

Members of the Austin Police Department block off part of Republic of Texas Boulevard following an explosion in Austin, Texas, March 19, 2018. Reuters/Sergio Flores

In March, Mark Conditt terrorized the Austin area with a string of bombings that killed two people, and wounded four others.

"They don't want to rule anything out," said Robert Elder, the retired ATF special agent in charge for the Houston area. "But you don't know that some person hasn't watched the news and for whatever reason decided that they want to try and mimic what occurred in Austin."

"I am very worried," said Pena.

Investigators have not confirmed that the two Beaumont incidents are related. But law enforcement sources say they're working on the assumption that they're connected.