After a shooting at Mercy Hospital in Chicago left four dead, including the gunman, on Monday afternoon, the president of the U.S. bishop's conference offered prayers for the victims and called for reasonable gun restrictions.

"Yesterday, at a place which should be a center of healing, a police officer, a doctor and a pharmaceutical resident lost their lives in a senseless act of gun violence," Cardinal Daniel DiNardo of Galveston-Houston said in a Nov. 20 statement.

"We entrust to Almighty God the victims and their loved ones and for [sic] the intercession of Our Lady of Guadalupe. May her love and compassion embrace and bring comfort to those who sorrow," he said.

According to reports, the shooting is being investigated as a domestic dispute. Dr. Tamara O'Neal, one of the victims, had been engaged to gunman Juan Lopez until September.

The other victims of the shooting were Dayna Less, 25, a pharmacy resident and recent graduate of Purdue University, and police officer Samuel Jimenez, 28, who was responding to the shooting.

Lopez was found dead with gunshot wounds to the head; it is unclear if they were self-inflicted or if they were sustained while he exchanged gunfire with police.

Lopez had worked for Chicago Housing Authority, which said in a statement after the shooting that Lopez had cleared background checks and did not have a history of complaints against him during his employment there.

In his statement, DiNardo said the shooting yet again called into question how someone "capable of such violence was able to obtain a firearm to carry out this heinous act."

"In our desire to help promote a culture of life, we bishops will continue to ask that public policies be supported to enact reasonable gun measures to help curb this pervasive plague of gun violence. Our prayers are with the staff of Mercy Hospital and the people of the Archdiocese of Chicago as they continue God's healing work."