Spanish police arrested a man who allegedly recorded upskirt videos involving more than 500 unsuspecting women.

The National Police arrested him while he was allegedly recording underneath a woman’s skirt while he was on a Madrid subway.

They posted video of the arrest on Twitter on Wednesday, describing the suspect as “one of the biggest predators of women's privacy.”

The man, who hasn’t been publically identified, allegedly recorded underneath the skirts of women while they were on the subway or while they were grocery shopping.

Spanish police allege he uploaded 283 of these upskirting videos – which featured 555 victims -- onto his website.

According to the police press release, the investigation began after “agents located a web portal dedicated to the publication of videos of explicit sexual and pornographic content with more than 20 million followers.”

After his arrest, police say they searched his home and discovered hard drives filled with illicit images.

They said they identified 29 women on the recordings, some of whom are minors.