The problem started about a week ago but seems to have escalated over the past few days. Hackers are breaking into legitimate Gmail accounts and then using them to send spam messages. Google is investigating a growing number of reports that hackers are using Gmail accounts to send messages. The problem has been reported to be growing in recent days, but has escalated in the last few days, Google says. Read the full article here: http://www.dailymailonline.com/news/newsknew/storystory/storyline/article-storyline-storylines-to-report-continue-up.
Source: https://threatpost.com/google-investigates-hijacked-email-accounts-042110/73857/