The U.K. Competition and Markets Authority announced that it has launched a merger investigation into Amazon.com’s IRBT -0.58% deal to purchase iRobot AMZN -0.22% and set a deadline of June 16 for its first phase decision. The regulator said previously that it was evaluating whether the deal could result in a significant lessening of the competition in any or all markets for goods and services in the United Kingdom. Amazon announced last year that it would buy iRobot in cash for $1.7 billion or $61 per share.