Executive infighting reportedly led to BlackBerry's downfall

In the end, BlackBerry's leadership may have been its own worst enemy.

The struggling handset maker suffered from infighting at its executive level that hobbled its ability to compete in the mobile market and led to its eventual downfall, according to an investigation conducted by the The Globe and Mail newspaper.

The company, which plans to cut roughly 40 percent of its staff and sell itself to an investment group, announced Friday that it lost $965 million last year. The biggest reason for the dramatic loss was the $934 million write-down the company took on inventory of the BlackBerry Z10, which apparently did not sell well.