An auxiliary policeman was shot and killed Sunday defending the home of Cardinal Norberto Rivera, the retired Archbishop of Mexico City.

The guard died on his way to hospital shortly after the shooting on Oct. 21. The cardinal was home during the attack but is reported to be safe and unharmed by the incident.

According to the Associated Press, the shooting was not an attempt on the cardinal's life, but has been presumed to be an attempted robbery.

The guard had been approached by two unknown attackers, who were pretending to deliver a package. After the suspects rang the doorbell, the guard opened the door and was shot.

Reuters reported that at least one of the men had been dressed in military clothes, and, after gun fire broke out, the man was forced back as shots were returned by other guards.

The Mexican bishops' conference expressed "its closeness, solidarity and support" to the cardinal, and offered prayers for the family and the soul of the slain officer.

Rivera retired as Mexico City's archbishop in December 2017.