Calling the blessing service unconstitutional, the group says the Bergen County Animal Shelter (BCAS), which is funded by the Department of Health Services and receives money from the government, is in clear violation of the First and Fourteenth Amendment, according to NJ.com.
Pictured with staff members was Reverend Kenneth Reihl of the Franciscan Order of the Divine Mercy.
"I've lived in New Jersey for more than 20 years," David Silverman, president of American Atheists, said in a statement. "When I walk into a government building to use government services, the government should be absolutely neutral on religious matters. Allowing a Franciscan friar to conduct religious services with staff is the antithesis of neutrality."
Candice Yaacobi, a fellow New Jerseyite, was identified in the suit as feeling ostracized and "inferior" for not have the same religious beliefs when going to the shelter during one of the days the blessing service was being held.
"As a humanist atheist, being forced into an encounter with a member of clergy in order to avail herself of government services sent Candice the message that the BCAS and Bergen County regarded her as inferior to those citizens who happened to adhere to the favored religious view," American Atheists wrote in its complaint.
Despite the group sending a letter to Debra Yankow, the animal shelter's director, to cease the service, the center later instead opted to promote another blessing event for residents.
"This is a suit that we shouldn't have had to file," Geoffrey Blackwell, lawyer for the American Atheists group, told IB Times. "We warned the shelter that using government resources to promote a religious event was unconstitutional, but they chose to ignore our concerns."
"What's more, by holding the event during business hours in a government facility, they sent the unmistakable message to anyone visiting the shelter that Bergen County endorses a particular religious view," the lawyer added.
Speaking to NJ.com, Blackwell quipped, "I thought it was well-settled that all dogs already go to heaven."
In addition to the animal shelter suit, American Atheists made headline news in 2016 for its national billboard campaign against Christmas.