“This cell phone case is a terrible idea,” the department said in a Facebook posting. “Officers do not have the luxury of time when making split-second decisions while interacting with the public.”

The prosecutor’s office in Ocean County, N.J., also commented on Facebook.

“Please folks — this cell phone case is not a cool product or a good idea,” the posting read. “A police officers job is hard enough, without having to make a split second decision in the dark of night when someone decides without thinking to pull this out while stopped for a motor vehicle violation.”

In what appeared to be the first remarks on the issue by a federal legislator, Senator Chuck Schumer said Tuesday that sales of the cases might be illegal and urged online retailers, including Amazon and eBay, to immediately stop selling them.

On Tuesday evening, a spokesman for Amazon, Erik Fairleigh, said in an email that the item was no longer listed for sale on the site. He declined to elaborate.