Yahoo employees thought they were safe from Marissa Mayer's layoffs after last month. They were wrong.

About a month ago, Yahoo employees showed up to work one day to find that suddenly, two to three conference rooms on every floor had been taken over by human resources.

That day, somewhere between 100 and 200 employees lost their jobs in a layoff management described as an organizational realignment.

After the day was over, the rest of Yahoo's employees thought their jobs were safe.

Many of them were wrong.

Since that day in February, the group firings at Yahoo have continued at a steady, almost weekly pace.

There were more just this week, sources close to Yahoo employees tell us.

One source says teams were cut in Yahoo's Sunnyvale, New York, and Burbank offices. Another source says that, unlike in the first round of cuts a month ago, Yahoo let go of some engineers this time.

"She's been laying people off every Wednesday," says a source who was just let go.

"I got let go last Wednesday along with about 10 people in my group (search). The week prior, I had coworkers in the homepage team get let go - again on a Wednesday."

"The word is that she's purposely going for small layoffs each week between different groups so as to keep it low key."

CEO Marissa Mayer has been under pressure to cut costs at Yahoo since before she formally accepted the job in 2012. Instead of deploying broad layoffs, Mayer has favored a system that ranks employees and dismisses those with poor scores. The system is unpopular with many employees. In 2013, employee gripes over it culminated in a meeting in which Mayer read to employees from a children's book.

In January, Yahoo announced that it would spin off its stake in Alibaba into a new company. Perhaps Mayer is trying to get the core Yahoo business into a better cost-structure before that deal finalizes in September.

We reached out to Yahoo for comment on this story and have not gotten a response in over 24 hours.

We'd like to keep hearing from Yahoo employees. They should email nicholas@businessinsider.com.