He regularly works the speed bag for technique and conditioning.

WSJ: What's Your Workout? A Skater's Edge

Summing up the evidence, Wilcox said it was "extremely unlikely, " but not impossible, that Williams had worked out a technique to get into the bag -- measuring just 32 inches by 19 inches (81 by 48 centimeters) -- and lock it from the inside.

CNN: STORY HIGHLIGHTS