The owner and manager of two affordable senior housing apartment complexes in Oklahoma are under investigation for alleged religious discrimination after removing Bibles and Christian reading materials from common areas.

U.S. Department of Housing and Urban Development Secretary Ben Carson announced Friday that he initiated a complaint against Coweta, OK-based Carriage Crossing and Collinsville, OK-based Cardinal Heights apartments, Wilhoit Properties and Vintage Housing. They are accused of violating the Fair Housing Act, which prohibits discrimination in housing and housing-related services based on religion and other protected characteristics.

Wilhoit, of Springfield, MO, manages the apartment complexes as well as more than 200 other properties in 16 states. Vintage Housing, of Newport Beach, CA, owns the two properties. The complaint was initiated after a Carriage Crossing resident sent a letter to HUD  “upset that the management demanded the removal of religious reading material from the common areas and angel ornaments from the complex’s Christmas tree,” according to a HUD news release.

HUD secretary-initiated complaints can be filed in cases “involving significant issues that are national in scope” or when the department is made aware of violations of the Fair Housing Act and “broad public interest relief is warranted.” HUD will conduct a fact-finding investigation to determine whether a discrimination charge will be filed.