The seemingly minor incident occurred last February when a nun in the town of Pozuelo de Alarcón (Madrid) was renewing her ID at her local police station.
To confirm that the sister had indeed provided a photo of herself, police officers asked her to remove her headgear to make her face visible, as common protocol stipulates.
News of the routine check somehow went on to reach the archbishopric and then the upper echelons of Spain's interior ministry.
Interior Minister Férnandez Díaz, himself a devout Catholic and member of the influential religious group Opus Dei, then ordered an investigation into the matter.
When the policemen who asked the sister to remove her veil were questioned, the ministry established that the agents had indeed behaved in the appropriate manner.
What has shocked the Spanish public is the importance given to the incident.
According to news daily 20minutos, hundreds of more serious incidents are completely overlooked by the ministry every day.
However, Fernández has spoken openly about his devotion to Opus Dei.
"My life plan is closely linked to Opus Dei's spirituality: go to mass every day, say a Hail Mary, pray for a while, then a spiritual reading," he is quoted as having said in an interview some years ago.
20minutos readers have responded to the news involving the nun, by commenting on the control religion still has over Spain's political upper class.
Some readers also referred to the fact that similar incidents where Muslim women have been asked by police to remove their headgear haven't been given the same importance by the government.
Opus Dei is a religious institution which is alleged to have held great power over Spanish politics since the Franco Regime.
Founded by Aragonese Roman Catholic priest Josemaria Escriva in 1928, it has commonly been linked to right-wing governments and influential families in Spain.