Twitter Inc, whose internal systems were breached by hackers two ago, stated a “spear-phishing” attack on a small number of employees through a phone led to the security incident.

Hackers targeted the U.S. microblogging site managed to breach 130 accounts, managed to access the inbox of 36 accounts and tweeted from 45 of them; they were also able to download Twitter data from seven.

In a statement, Twitter said the hackers targeted specific employees who had access to account support tools, and added that it was able to restrict access to to its internal tools and systems following the cyber security incident.

According to publicly available blockchain records, the apparent scammers were able to receive more than $100,000 worth of cryptocurrency.

The “spear-phishing” technique is a practice of sending emails ostensibly from a known or trusted sender in order to induce targeted individuals to reveal confidential information.