21.   The complications included serious infections, bleeding and mechanical malfunctions like motor failure, kinking of the tubes and worn bearings.

22.   The decision is significant because it would, in effect, declare that authorities suspect the crash was caused by a criminal act, not a mechanical malfunction.

23.   The explosion was almost certainly not caused by a bomb at all, investigators say, but by some mysterious and catastrophic mechanical malfunction.

24.   The investigators acknowledge that they have no evidence pointing to a mechanical malfunction.

25.   The mechanical malfunction snapped his three-race winning streak, but also put some drama back on the NASCAR circuit.

26.   The problems that have arisen in recent months reflect a lack of training of officers rather than any mechanical malfunction of the weapon, the former police official said.

27.   The safety board, meanwhile, has explored a variety of theories for how a mechanical malfunction could have created a spark to set off the explosion.

28.   Their black boxes seemed to rule out mechanical malfunction.

29.   Then, he said, investigators may be able to determine if human error or some mechanical malfunction, including static electricity, sparked the explosion.

30.   There, the lack of evidence of a crime has, almost by default, increased the probability of a mechanical malfunction.