Two so-called “black widow” robberies targeting tourists in Buenos Aires gained traction over the weekend after four men were drugged by groups of women they met partying and had their possessions taken.

On Friday, a French tourist reported to the Buenos Aires City police that at about 5:30 a.m. that morning he went back to his apartment in Almagro with three women he had met in the area of Plaza Serrano in Palermo Soho.

According to the Buenos Aires City police the last thing he remembers was drinking with the women at his apartment. He woke up several hours later to find that his computer, cell phone, a speaker, and wallet with money and debit and credit cards were missing.

The Herald could not independently verify widely-circulated videos claiming to be of the incident, showing a total of five women involved. The footage shows three women enter the apartment building with the man, and one later opens the door to let in another accomplice. Five women can then be seen exiting the building with a large rolling suitcase.

A similar robbery reportedly occurred at 5 a.m. on Sunday morning. Three Uruguayan tourists reported that their cell phones and money were taken by two women who they met at a night club and then invited back to their apartment. Once there, the men said that they continued to drink and then lost consciousness, waking up at about 5 p.m. Sunday afternoon, when they realized the items and money were missing.

The United States Embassy in Argentina sent out an alert last August notifying foreigners of an increase in reported robberies involving drugs that temporarily incapacitate victims targeted in bars, nightclubs, and through dating applications.

The alert advises individuals to avoid leaving food or drinks unattended at a bar or restaurant and to refuse offers of something to eat or drink from a stranger. It also urges exercising caution before inviting individuals back to one’s hotel or residence.

Another precaution is to tell a friend or family member of plans, including where you are going, details of the person you are meeting, and the app you used to meet them. Victims who are targeted via online dating applications tend to have their electronic devices stolen, which often contain all evidence of communication with the assailants.