Home security company Verisure said it had detected unauthorized access to customer data linked to one of its subsidiaries.

The breach affected systems belonging to Alert Alarm, a Swedish home security brand that Verisure acquired several years ago, the company said. The subsidiary’s IT infrastructure is managed separately from Verisure’s main network and hosted by an external billing partner.

In a statement on Friday, Verisure said the intrusion was confined to that system and did not impact its broader operations in Europe and Latin America. Based in Sweden, the company has operations in 17 countries overall.

The incident came just a week after Verisure’s €3.2 billion ($3.7 billion) initial public offering on the Stockholm stock exchange — the largest European IPO so far this year. Verisure’s shares fell more than 5% following reports of the breach.

According to the company, the compromised data includes names, addresses, email addresses and social security numbers of around 35,000 current and former Alert Alarm customers in Sweden. Alert Alarm currently serves fewer than 6,000 active customers.

“Forensic analysis has so far not identified any signs of intrusion within Verisure's own network or systems,” the company said.

Swedish police confirmed to local media that they have opened an investigation into suspected blackmail and an aggravated data breach, following a report filed by Verisure last week. Authorities have not specified when the incident occurred or who was behind it.

Verisure, which provides alarm systems, video surveillance, and emergency response services to households and small businesses, did not respond to a request for comment at the time of publication.

“The investigation is ongoing, and we will update Alert Alarm customers when further information is available,” the company said in a statement.