MODESTO -- The House Modesto is a place of worship where thousands come to feel grounded in their faith.
But on Oct. 1, Rebecca Markert with the Freedom from Religion Foundation says Pastor Glen Berteau endorsed a candidate running in the Modesto Irrigation District race.
"In this case, we did hear from multiple people about the illegal electioneering happening at The House Modesto and asked us to get involved," Markert said.
So her organization decided to act, and sent a letter to the IRS asking them to investigate.
Markert, who spoke to FOX40 over the phone, says the goal of the organization is to defend the constitutional separation between church and state.
She says just over a month before Tuesday's election, Stu Gilman -- a candidate for MID director -- spoke to the congregation about why he wants their vote.
Markert says this sermon could cost the church their nonprofit status.
"Not only did they allow him to speak at their worship services, but they also allowed him to hand out campaign paraphernalia," she said.
Since the 1950s, the Johnson Act has forbidden 501(c)(3) organizations like The House Modesto from endorsing political candidates.
Video of the sermon has since been taken down, but according to the foundation, Pastor Berteau was heard saying to Gilman in front of the congregation:
"Let me know in each of those districts that come up for election, I want to let our church know whatever area they're in so we can vote and get a right guy in there, OK?"
"That also signals endorsement," Markert said.
Pastor Berteau did not want to go on camera, but in a statement, called the letter "frivolous, untrue and not factual."
He said, "I'm not scared of any kind of accusation because I have allowed politicians within my church. To take one instance, and say he is breaking the law, is ridiculous."
As for Gilman's opponent -- incumbent Jake Wenger -- he says The House never invited him to speak.
"Generally speaking, 501(c)(3) organizations don't invite political candidates, so it's never been a thought of mine to go and ask to speak, nor have I been asked," Wenger said.